[Insert some welcome text to start, and remember, it doesn't have to be perfect the first time. You can always come back and edit it, delete it, add more or start again! Here's an example:]
We've got a project to finish, and this site is a central point to keep track of our goals, the project schedule, and our work in progress. Add pages as necessary, brainstorm on the wiki "whiteboard" page, and use the person-to-person messaging feature to keep in touch with team members.