User Stories are an important component of any Agile project. Here is a sample one (from the agile alliance):
Title: Search for providers by provider specialty.
As a provider search user, I need the ability to search for providers by specialty so that I can more efficiently refer patients to specialists.
The provider search mechanism has the ability to enter a specialty.
The specialty search will have a list of provider specialties from which to select.
Searching via the provider specialty will return a list of matching specialists or a message indicating that there are no matches.
If there are more results than can fit on one page, the system will provide the capability to view the list in pages or sections.