See my review of Norton Internet Security for Mac under Norton Anti-Virus. NIS for mac includes Norton Firewall. Also, this is a very user friendly application. If you find it's not, you need to read the instructions.

I've got nothing against Norton other that I've red so much bad reviews on Norton and Macs in general, but have you guys tried the Intego NetBarrier X4? I just got broadband and I thought I'd spend a little extra for extra security and I was sooo impressed at all its features, check it out for yourself, here's the link to their site: http://www.intego.com/netbarrier/

I really like NPF. It gives you SO much information about what's going on. It not only tracks almost every type of hit, but you can also click on it and actually get an idea of WHAT IT IS. You can even trace it back to its source, VISUALLY and by address lookup. NPF even suggests action you can take if you don't like the hit. It has stealth mode, a link to the Norton security test, and a few quick setup configuration options. You can check connected users.Our Mac mentality has us so used to bashing big companies that we're overlooking at least one company (Symantec) that is doing things right. Only complaint -- Panther update took too long.