So far, there are 2 projects/products using agile software development.

There are 4 type workitems used in agile software development: user stories, tasks, test cases, bugs

1. user stories

A team creates user stories to define the features, functions, and requirements to be implemented. A user story describes customer goals at a high level and are fundamental elements of the team's planning effort because they help the team estimate, prioritize, define, schedule, and verify work that relates to each user story.

Each user story should simply state what a user wants to do with a feature of the software and describe it from the user's perspective. When you write user stories, you should focus on who the feature is for, what they want to accomplish, and why . You should avoid descriptions that specify how the feature should be developed.

The format is like :

"As a <role>, I want <goal/desire> so that <benefit>"

or much shorter version: "As a <role>, I want <goal/desire>"

2. tasks

A task communicates the need to do some work. Each team member(dev, tester, ui) can define tasks to represent the work that they need to accomplish.

3. test cases

A team uses test cases to define both manual and automated tests. We can create not only test cases but also test suites and test configurations that support testing your project.

4. bugs

A bug communicates that a potential problem exists in the code that your team is developing. When you define a bug, you want to accurately report the problem in a way that helps the reader to understand the full impact of the problem. You should also describe the actions that you took to find the bug so that other members of the team can more easily reproduce the behavior. The test results should clearly show the problem.

Please refer to http://msdn.microsoft.com/en-us/library/dd380634.aspx#AddTestCase

and http://www.subcide.com/articles/how-to-write-meaningful-user-stories/

and http://en.wikipedia.org/wiki/User_story

Agile software development