From Koingo Software:
Sharing files across your local network just got easier! Swift Share allows the easy creation of both Windows and Macintosh share points. Take control of Mac OS X's built-in file servers and tweak them to perfection. Share points are points across the network at which remote users can access your files. Mac OS X gives you one default share point: your home directory. However, if you're anywhere but home, you won't want to be giving everyone access to your entire home directory! Using Swift Share, choose only which folders you want to share and which users have access.
The power of Swift Share doesn't end at its ability to manage your share points. It also offers unique flexibility to manage users and groups on your system. For instance, create a new group of sharing-only users to access a "Games" folder on your computer.
Swift Share also gives you more than just start and stop controls for the powerful file servers built-in to Mac OS X. Customize nearly one hundred aspects of the Apple and Windows file servers. From user limits, guest permissions, and logging to workgroups, authorization modes, and greetings.