Recently I ordered a Macro Extension Kit from Fotodiox. The five piece Kit is made up of 3 extension rings and 2 mounts. This is an inexpensive kit that can greatly improve your existing Canon lens macro capability, but not with out some braw backs.
The main drawback, this kit is non powered. So IS and auto focus are out of the picture (pun intended). You do not have the ability to control your aperture with this kit as well. Also this kit will throw your camera off balance. It is awkward as a hand held accessory add-on. However, with a coast of $11, the price on this kit easily helps me ignore those detriments. So if you don’t mind the downsides of this kit and have a few bucks to spare. you will have an inexpensive attachment that will give you a 1:1.3 Macro true to life scale. Personally, I think it was 11 dollars well spent, even if it’s just used as a toy.