Users & Groups for Mac

From Fruit Bat Software:

Users & Groups is an Application/PreferencePane that allows more control over Mac OS X User and Group accounts than Apple's built-in Accounts PreferencePane. Not only can you do everything the Apple Accounts prefPane does it extends control over many hidden but usefull user attributes, you can also create, edit, and delete User and Group accounts.
Change a User's short name, real name, uid, password (including login keychain password), home directory (move, create new, or reassign), user's default shell, administrator privileges, and group membership.

Manage all of your AutoMounts from within the application including Apple(HFS or AFP), NFS, SMB (CIFS), FTP and WEBDAV