I'm using a 32MB Memory Pro Duo card from my PSP, so in case I need to, I can also destroy it physically.
Step 1: Preparations
After that, you will need to download TrueCrypt from truecrypt.org. Install it, and reboot your PC (this is mandatory)
Step 2: Setting Up Our Volume - 1
Step 3: Follow the TrueCrypt Wizard
Select "hidden Truecrypt volume". this is an advanced type of volume. if for some reason, you have files that you REALLY want to hide, this lets you create two volumes with two passwords, and each password will give you access to a different volume.
When it asks to select a file, choose the file you previously copied over to your storage medium.
For this outer volume, choose serpent-twofish-aes. Outer volume is a decoy volume. Keep the hash algorithm at the default.
Choose a small volume for the outer to make it not look suspicious (a small jpg shouldnt be 20mb in size)
Choose a password that you can easily guess.
Make sure filesystem is fat, cluster is default
Now, read the image I uploaded that is titled "Outer Volume Contents" and follow those directions.
Click next, follow the same procedure to make your hidden volume.
Only difference here, for the password, check 'use keyfiles'. Select a file no one will likely modify. I chose the overweight dog image. Never modify that file, or you will not be able to access your volume anymore. Choose a long password (64 characters in length) to avoid being cracked by brute force. This is up to you, a long password isn't necessary unless you're hiding life-threatening documents. If you're just hiding porn, any password will do.