Truecrypt allows you 2 create hidden volumes.
When you create a new encrypted volume, it gives you the option of created a hidden volume.
Basically your encrypted partition or file has 2 parts 2 it & you set a different password for each.
If you're forced to give up the password, give the password to the decoy volume.
Becos the data on the volume is randomized, there is no way to prove or even detect if there is a hidden volume.
Have a look at the truecrypt dox & search for Hidden Volume