TuneTracker is designed to give you a detailed song list. You can download a tune's "template" and mark how well you know it and when you last played it in seconds. Then, while you're practicing you can sort through the songs you know the least. When you're getting ready to perform, you can quickly check the songs you know the best!
TuneTracker is planned to have new features in the future, including the ability to see which songs you and your friends both know, the ability to see which songs are popular in certain areas, giving users "points" for contributing information about songs, and many other ideas!