It is quite simple to set up encrypted volumes using truecrypt. If you mount the encrypted disks at boot time, then an annoyance is having truecrypt prompt for password or path to key for each disk. You can specify these things on the command line while mounting the encrypted volumes, but for a very large reasons that is not a clever approach.
In this guide, I will discuss how to set up an usb device with some random, compressed files on it, working as keyfiles for the devices encrypted by truecrypt. Then I will present the boot time script, mounting the specified key device, and mounting the volumed with truecrypt and the key files stored on the usb device.
Firstly, prepare the key device. Any old mp3 player or what ever will suffice.