Ciphering /coding software

Hi

Im looking for software which would allow me to code my hdd (AES 256 coding method would be great)
Maybe having chance to pick length of code key too? Anyways im thinking of copying pass/access key to pendrive, so that nobody who havent got it, wont be able to access my pc

Any advices?

http://www.truecrypt.org/

aes 256 really is over kill for personnel data on your hard drive. Just remember the stronger the encryption generally the longer it takes to decrypt so the slower your computers going to run.