The bowline is an invaluable knot for the outdoors-man. Not only can it be used for climbing, a properly tied bowline will hold under extreme circumstances, yet still be easy to undo if necessary.
Step 1: Prepare to Tie
I prefer tying the knot around my waist, however, since I cannot do that, and take pictures, I will be using the back of a chair. I would recommend that you tie it around your waist. Begin by grabbing one end with each hand, with the rope going behind you and your arms extended.
Step 2: Tie the Knot (No Pun Intended... or Really Possible in This Context)
This is pretty much impossible to describe, so you're going to want to pay very close attention to the images in this step.
Step 3: Afterthought
If at first you get it wrong, keep retrying. It takes a lot of practice to master the bowline, so don't become discouraged if it's hard.