Is there a cross platform way to encrypt a USB thumb drive partition?

Question

Possible Duplicate:
Encryption Program for Flash drive data

I sometimes carry sensitive data around on a thumb drive when travelling overseas. However, ideally it should be encrypted. I use Linux & Windows (and mac sometimes), but would like something automatic so that I don't have to think too hard about encrypting it. That's why I don't like the archive approach. I like that linux can recognise the encrypted drive automatically. I think windows 7 have something similar now?

I like the way this works: http://www.emcken.dk/weblog/archives/164-encrypted-usb-drive-in-ubuntu.html

And someone even mentions doing it through ntfs driver under linux but ran into some problems. Could that work under windows 7 too?

I know there are hardware based solutions out there, but they involve more expense and you're not able to turn what you already have into an encrypted drive.

Has anyone had cross-platform success with this with encrypting thumb drives under ubuntu that also worked under windows 7 or mac?