NoobProof was a IPFW firewall configuration tool for Mac OS X.   Very easy, just follow the 5 steps how-to in the application help.
You can also tune bandwidth, manage black lists and create self-configuration tools called injectors.
The first time you launch NoobProof the Wizard will help you configuring the Mac OS X firewall. 

• uses Mac OS X built-in IPFW firewall. No kernel modules, no extensions, no pain. NoobProof is free and open-source
• decide who can connect to your mac's open services: allow or deny a single host, multiple hosts or subnets for every configured service
• deny unwanted connections to shared files, music, photos, printers
• easily add new custom services and rules
• limit inbound bandwidth for selected services or for all Internet traffic
• deny real-time network applications like on-line gaming or audio/video chatting
• block untrusted hosts with outgoing/incoming connections black lists
• see firewall logs in window, in terminal or in real-time
• see live static and dynamic ipfw rules
• supernoob mode one-click firewall setup (stateful firewall)
• wizard configurator is the easiest way to configure the Mac OS X firewall. It starts the first time you launch NoobProof
• friendly default configuration, very simple graphic interface
• injectors: easily deploy your firewall setup across a large number of macs; do backups or libraries of useful firewall configurations. Injector works on Mac OS X 10.4-10.7.

Please note:

• hanynet.com applications are NOT available on the Mac App Store because Apple does not allow AppleScriptStudio applications to be listed on the Mac App Store. AppleScriptStudio is the development technology we used to develop applications since 2005.
• hanynet.com applications are NOT signed with Apple GateKeeper technology because Hanynet's applications are OPEN SOURCE. You don't need any sign to trust Hanynet's application because you (and the Mac community) has FREE ACCESS TO ITS SOURCE CODE.