What is Agile?
Agile is an iterative, team-based approach to development. This approach emphasizes the rapid delivery of an application in complete functional components. Rather than creating tasks and schedules, all the time is "time-boxed" into phases called "sprints". Each sprint has a defined duration (usually in weeks) with a running list of deliverables, planned one sprint in advance. Deliverables are prioritized by business value as determined by the customer. If all planned work for cannot be completed, work is re-prioritized and the information is used for future sprint planning.
As work is completed during each sprint, it is continuously reviewed and evaluated by the customer, who may be considered the most critical member of the Agile team. As a result, Agile relies on a very high level of customer involvement throughout the project.