Well, none of the items linked to me do the trick. Honestly, I love mac, but the fact that I can't password protect my files is pretty pathetic. I'll just have to utilize the windows emulation so I can use Office 07, you can encrypt your files with that easily.
I'm a latecomer to the thread, stumbling my way here from a Google search. I found 3 of the linked solutions worked perfectly (DashCrypt, Crypt3, and jFileCrypt). Crypt3 gets my vote for combined simplicity with ability to shred original file, something the other two don't do.