I'm a user of TrueCrypt for my hard drives, but I want something like Kingston's Secure Traveler software that allows you to partition a flash drive into encrypted and non-encrypted partitions. I've got a Kingston Data Traveller II 1GB flash drive that I've split into two 500mb partitions - one of which is encrypted.
I've tried using the software on my new 4GB OCZ Rally2 stick, but the software won't run unless it's on a Kingston drive. I've found software that will encrypt the entire drive (like TrueCrypt) and software that will encrypt specific files or folders, but these aren't nearly as convenient or as fast as the Secure Traveler software.