FreeOTFE is a lot like TrueCrypt but comes with another piece of software, FreeOTFE Explorer, that allows you to browse the drive without having administrator privileges.
From their website:
Highly portable - Not only does FreeOTFE offer "portable mode", eliminating the need for it to be installed before use, it also offers FreeOTFE Explorer - a system which allows FreeOTFE volumes to be accessed not only without installing any software, but also on PCs where no administrator rights are available. This makes it ideal for use (for example) with USB flash drives, and when visiting Internet Cafés (AKA Cybercafés), where PCs are available for use, but only as a "standard" user.
In addition, you may also consider reading the Lifehacker guide to locking down a flash drive.
Another option you may like is to conduct everything over SSH. Despite leaving the data on a live computer, you get the added benefit of access control and letting different people use different passwords.
Just promise me, though, you won't be helping al Qaeda with this encryption ;-).