I operate my web and print design business as a sole proprietorship. It's easier and cheaper for me to do the taxes that way.
If you operate under a name other than your own you have to register that name. You are still able to file your taxes as you would a normal freelancer.
The only benefit I've found to incorporating is that you reduce your risk in case of a lawsuit. Right now, someone could sue me and everything I own would be fair game.
Here's the Alberta government site about starting a business that has lots of useful information:
http://sbinfocanada.about.com/cs/sta...regalberta.htm