Canon will charge you about Â£30 for one of the these ... cost to me ... nothing ... it was all stuff I had lying about the house.
Step 1: Find a Cable
Luckily I had one lying about but they can be purchased for all of about Â£3 from any decent electronics store. Make sure it has 4 cores as you will need two pairs to control both the exposure and shutter. If needs be cut the cable and touch the ends together while connected to the camera to check which is which.
Step 2: Tools for the Job
Step 3: Operation
Be careful and enjoy, if you have any doubts, don't do it!