Rails users, I finaly released the auth_generator v1.5.0. You can now use your favorite crypting algo (md5, sha, make your own, salted depending of the login) to store passwords.
You now have unit testing for the model. You can disable account creation if you wish, select the size of the buddy icons. And there is a trac too!
Auth_generator is an authentification generator for rails. It gives you a complete administration interface to handle users. You should be able to install it within minutes.
Update, Please use the 1.5.1 version. The 1.5.0 is broken, !$@.
Another update, You should use 1.5.2 in fact, 1.5.1 was still broken!