Pick up a copy of PGP for your machine:
(All platforms are supported. It is illegal to download this software in the US without reading one of the following READMEs first, but the rest of the world's WinDoze users can download it immediately from England,
Norway,
Germany,
or Italy.
And don't keep it on your powerbook on your trip overseas because you will be considered an international arms smuggler by the US government. If you're in the US you can read one of the following files and follow the instructions to download the copy of PGP that best suits your machine. If you are overseas and you use a Mac, ask someone else how to find MacPGP.)
Sites for Macintosh Users: (I've left out the usual places like www.apple.com (duh) and Infomac mirrors; if you want these look for them in one of the following sites). Oh yeah and non-Mac users should visit MicroSnot.