Hi folks.
The Backtrack 4 USB Drive How-to has undergone a huge re-write. One of the largest changes is that we are no longer using UNetBootin except for one minor thing and then only if you want to. Everything is done from within Backtrack itself now.
Another change is that I have added instructions on setting up encryption with Truecrypt directly into the how-to. Finally, I have added some interesting tweaks such as mounting the Truecrypt volume on boot, changing root's home directory to the encrypted volume on the fly and setting nessus up to log to the encrypted directory.
It still lives in the same place.
If you were using the old how-to and don't want to start over, it is living here now. The parts of the new how-to on encryption and tweaks will still work with the old how-to if you just want to add that bit.
As always, let me know of any problems, typos, mistakes, etc. of which I am sure there are plenty. 
-Kevin