wachtwoord, dude, I gave you
the link to official Tails description on how to use Truecrypt, how can I unambiguify it more? Except if you are using some software called TrueScrypt, I can`t help then, lol

Also I won`t teach you how to use Truecrypt itself, I`ll leave it to
very good documentation and Mr. Google
I suggest you to install Tails with its built-in installer to USB and configure Persistent volume with built-in configure tool. It is easier and more "official way" than Truecrypt in Tails.
Come on N.Z., go a little easy on the linux-n00b

I remember those days... lots of confusing command line arguments, figuring out how to re-add windows to my grub menu, the dreadful "kernel panic"... great fun!
If I get some time, I might try the Tails thing, too. Maybe I can write up a more-specific instructions. I think having an 'offline" setup that doesn't require separate hardware is a nice alternative.
Specific instructions for Tails or UPR would be great. Or even better, a downloadable ISO including armory for a Tails / UPR livecd.
The only inconvenience in Tails is the difficulty in creating an USB with persistence that will boot on macs. I found a workaround using one CD with refit + Tails USB 1 made with Unetbootin + Tails USB 2 made with the Live USB Installer inside Tails.
The system will boot with the CD + USB 1, but the OS will run in USB 2, with persistence (don't ask me why).
If you use only refit + USB 2 Tails will not boot on a mac.
It's not the best way, but at least works.