[BLUG] look for encryption solution for a USB drive

I use the computers on campus frequently and use a usb drive for portable apps and to store my documents.  I had been wanting to find some sort of encryption solution for a while, but of course it takes me actually losing a drive to decide to find one.  Truecrypt looks pretty cool, and they even have a traveler mode whereby you can encrypt parts of the drive and have an executable version of truecrypt to decrypt the files w/out having to install it. However, even this mode requires admin access.  Short of buying a usb drive with some sort of built in encryption option, is there are software solution that doesn't require root access?  It would also be really nice if it wasn't windows only as I use both pcs and macs on campus and ubuntu/vista at home.  

thanks

Ben