Free PHP User Management Script: LOG.ME.IN
LOG.ME.IN is a free PHP user management script for easily protecting site content and displaying it to only registered users.
It is also an instant solution for creating the common membership modules like sign-up, login or "forgot password".
The script uses MySQL as the database and has a web-based installer for a quick installation.
LOG.ME.IN has a strong focus on security: it is integrated with reCAPTCHA, performs a safe session handling and SQL injection/XSS proof.
And, it has a back-end to manage users (listing, editing and deleting them).