The smog pump's function is to inject air into the cats to help them warm up quicker and to help them last longer (so I've heard). If your looking at the engine, it will be at the lower left, with some tubes coming out of it. If you remove it you can either bypass it, or get an eliminator kit (which is the route I chose to take with my car), in which case, you can take the rest of the smog pump gear out, which makes for a good amount of more room in the engine bay. Sorry, but I don't have any pics.
If you're going to remove it don't even waste the money on the eliminator bracket, just run a shorter belt. And if you do take it off don't forget to pull the tab & tad valves inside the fender.
on edit: forgot to mention that you will need to re-clock the belt tensioner.