A few years back I wrote about a tethering software for Nikon, called (funnily enough) ControlMyNikon, which the developer had only made available for certain Nikon bodies.
Now he's made a version of ControlMyNikon for Canon bodies too .. hence the name ControlMyCanon!
Anyhow, it's said to be the same program as ControlMyNikon, so the features are unbelievably long to mention in one post ... pretty awesome software if you want to automate a focus stack of a zillion images or whatever.
Anyhow ... look here: ControlMyCanon for a bit more info.
it seems he's bumped up his pricing since I got CMN a while back($9.95!) and now it's advertised for close to $30 .. but CMC is currently offered for US$20.
Note tho, I mentioned automated focus stacking, and to do this with ControlMy_ you will also need a focus stacking program. (I use the freeware CombineZP).