Rational Unified Process (RUP)is an object-oriented and Web-enabled program development methodology. According to Rational (developers of Rational Rose and the Unified Modeling Language), RUP is like an online mentor that provides guidelines, templates, and examples for all aspects and stages of program development. RUP and similar products -- such as Object-Oriented Software Process (OOSP), and the OPEN Process -- are comprehensive software engineering tools that combine the procedural aspects of development (such as defined stages, techniques, and practices) with other components of development (such as documents, models, manuals, code, and so on) within a unifying framework.
RUP establishes four phases of development, each of which is organized into a number of separate iterations that must satisfy defined criteria before the next phase is undertaken: in the Inception phase, developers define the scope of the project and its business case; in the Elaboration phase, developers analyze the project's needs in greater detail and define its architectural foundation; in the Construction phase, developers create the application design and source code; and in the Transition phase, developers deliver the system to users. RUP provides a prototype at the completion of each iteration. The product also includes process support for Java 2 Enterprise Edition (J2EE) and BEA (WebLogic) development, and supplies an HTML-based description of the unified process that an organization can customize for its own use.

The Waterfall model is a popular version of the systems development life cycle model for software engineering. Often considered the classic approach to the systems development life cycle, the waterfall model describes a development method that is linear and sequential. Waterfall development has distinct goals for each phase of development. Imagine a waterfall on the cliff of a steep mountain. Once the water has flowed over the edge of the cliff and has begun its journey down the side of the mountain, it cannot turn back. It is the same with waterfall development. Once a phase of development is completed, the development proceeds to the next phase and there is no turning back.

The advantage of waterfall development is that it allows for departmentalization and managerial control. A schedule can be set with deadlines for each stage of development and a product can proceed through the development process like a car in a carwash, and theoretically, be delivered on time. Development moves from Concept, through Design, Implementation, Testing, Installation, Troubleshooting, and ends up at Operation & Maintenance. Each phase of development proceeds in strict order, without any overlapping or iterative steps.

The disadvantage of waterfall development is that it does not allow for much reflection or revision. Once an application is in the testing stage, it is very difficult to go back and change something that was not well-thought out in the concept stage.

Agile Development is a methodology for the creative process that anticipates the need for flexibility and applies a level of pragmatism into the delivery of the finished product. Agile software development focuses on keeping code simple, testing often, and delivering functional bits of the application as soon as they're ready. The goal of ASD is to build upon small client-approved parts as the project progresses, as opposed to delivering one large application at the end of the project.

Extreme Programming (XP) is a deliberate and disciplined approach to software development. XP is used for risky projects with dynamic requirements to experience greater success and developer productivity. XP emphasizes customer involvement and promotes team work based on its simple rules and practices. Customers enjoy being partners in the software process and developers actively contribute regardless of experience level.
This methodology also emphasizes team work. Managers, customers, and developers are all part of a team dedicated to delivering quality software. XP implements a simple, yet effective way to enable groupware style development.
XP improves a software project in four essential ways: Communication, Simplicity, Feedback, and Courage. XP programmers communicate with their customers and fellow programmers. They keep their design simple and clean. They get feedback by testing their software starting on day one. They deliver the system to the customers as early as possible and implement changes as suggested. With this foundation XP programmers are able to courageously respond to changing requirements and technology.
The basic Rules and Practices in XP are

The Capability Maturity Model (CMM) is a methodology used to develop and refine an organization's software development process. The model describes a five-level evolutionary path of increasingly organized and systematically more mature processes. CMM was developed and is promoted by the Software Engineering Institute (SEI), a research and development center sponsored by the U.S. Department of Defense (DoD). SEI was founded in 1984 to address software engineering issues and, in a broad sense, to advance software engineering methodologies. More specifically, SEI was established to optimize the process of developing, acquiring, and maintaining heavily software-reliant systems for the DoD. Because the processes involved are equally applicable to the software industry as a whole, SEI advocates industry-wide adoption of the CMM.
CMM's Five Maturity Levels of Software Processes are:
At the initial level, processes are disorganized, even chaotic. Success is likely to depend on individual efforts, and is not considered to be repeatable, because processes would not be sufficiently defined and documented to allow them to be replicated.
At the repeatable level, basic project management techniques are established, and successes could be repeated, because the requisite processes would have been made established, defined, and documented.
At the defined level, an organization has developed its own standard software process through greater attention to documentation, standardization, and integration.
At the managed level, an organization monitors and controls its own processes through data collection and analysis.
At the optimizing level, processes are constantly being improved through monitoring feedback from current processes and introducing innovative processes to better serve the organization's particular needs.

ISO 9000 is a family of standards for quality management systems. ISO 9000 is maintained by ISO, the International Organization for Standardization and is administered by accreditation and certification bodies. Although the standards originated in manufacturing, they are now employed across a wide range of other types of organizations. A "product", in ISO vocabulary, can mean a physical object, or services, or software.

ISO 9001 is a series of documents that define requirements for the Quality Management System Standard. ISO 9001 is one of the documents in this set; it contains the actual requirements an organization must be in compliance with to become ISO 9001 Registered.ISO 9001:2000 is the current version of the Standard. It was revised in the year 2000. Past versions of ISO 9000 included ISO 9002 and ISO 2003, but those are no longer in use. Companies are now only Registered to ISO 9001.

The Project Management Institute (PMI®) is the world’s leading association for the project management profession. It administers a globally recognized, rigorous, education, and/or professional experience and examination-based professional credentialing program that maintains an ISO 9001 certification in Quality Management Systems. PMI professional credentials — available to members of the Institute and nonmembers alike — are widely recognized and accepted throughout the world as evidence of a proven level of education, knowledge and experience in project management.

Project Management Professional (PMP®) is a PMI driven initiative where a a PMP designation following an individuals name tells current and potential employers that they have demonstrated a solid foundation of knowledge from which you can competently practice project management. Eligibility for a PMP Credential, requires first meeting specific educational and project management experience requirements and agreeing to adhere to a code of professional conduct. The final step to becoming a PMP is passing a rigorous multiple-choice examination designed to objectively assess and measure your ability to apply project management knowledge in the following six domains : initiating the project, planning the project, executing the project, monitoring and controlling the project, closing the project, and professional and social responsibility .