Symmetric Encryption/Decryption Example

A friend of mine asked me today how one would go about encrypting something using the Rijndael algorithm (also known as AES) using the .NET framework. I’ve done some crypto work, so I whipped up a quick example for him. It turns out to be pretty much exactly the same as using any other symmetric algorithm like DES. I've posted the code and a brief explanation here.
[CraigBlog]

This is a nice example of Cryptography in .Net that might be handy to have a link to.