Forgotten Passwords

[eluser]Sean Murphy[/eluser]
I'm looking for ideas on how to build a good "forgotten password" system.

I just came up with what I think is an effective and easy solution, but I'm interested in how you do it. User experience and security are, of course, two very important things.

Oh, and ideally an email address would be the login credential, no "usernames".

Thanks in advance for any good ideas!