When is it a good idea to incorporate?

stairmaster writes: A couple of months ago I came across an opportunity to supplement my income by doing some consulting work (read mobile app development) on the side. It appears that I will be doing this work for some time and my question for you, the /. community, is this: is it worth it to incorporate as a business? I know that the answer to this question is extremely dependent on circumstance but I'm interested in your experiences. Have you been in a similar situation and if you have how did it work out for you?