With the different authentication provider support for MOSS, there are more and more free applications that will provide user management tools integrated in the SharePoint environment.
One very good example is the Forms Based User Administration Feature, which can be downloaded from codeplex.
Featurelist:
- The Feature includes an Administrator web part to view/edit/delete and add users to the data store by an administrator.
- Self registration page for users to request access to the site.
- New functionality for self registration
- Password retrieval via email
- CAPTCHA validation on self registration
- UI Enhancements