The MacGPG project
Privacy Guard (GPG) for MacOS X, along with a reference to quite
some useful tools which help integrating it nicely with other
Actually, I switched to
the MacPorts gnupg package recently,
support. To compile it:
$ sudo port install gnupg <em>+idea</em>
In case you don't need IDEA, the MacGPG package works just fine.
Either way, if you install GPG make sure to have a look at the Links
section. Especially GPG Keychain Access,
and ABKey are must-haves.