[Javascript] OT - User Management Software

[SkyScanner]

Hi - I need to add some user-management software to a new set of pages 
I'm working on. Basically, I want to allow people to sign up, log in, 
and then be able to visit certain password-only areas. They should be 
able to change password, pick their own usernames, request a lost 
password; all the usual kind of stuff. I want it to be PHP/MySQL based: 
hopefully a system that doesn't mind sharing a database.

I did the usual searches, and came up with UMA, but the help-forum 
doesn't make very encouraging reading, so I thought I'd see whether 
anyone had any recomendations? Free would be good!

Tim in Ireland.