my personal favorite is gpg4usb, it doesn't offer integration with programs but its simple work and easy to use/pick up.
http://www.gpg4usb.org/ Thanks for bringing this up, I had heard of it before but had forgotten. I'm definitely going to look into this. Also, I like the fact that I can carry it on a USB and take it with me where I go if needed. Although, I'm thinking I could carry other PGP programs on a USB stick as well? You can tell I'm pretty naive about all this even though I have done some research.