We found ours through Craigslist, and had appointments to look at several others that we found through there, too. Apartment People can be a helpful service (they drive you around and show you lots of different places) but they tend to concentrate on high-rises and more expensive places in "trendier" areas (Lincoln Park, Lakeview, etc.).

I would definitely recommend cruising around Craigslist a bunch, and also just walking around some of the neighborhoods you're considering and taking down numbers. There's a lot of places around here with "for rent" signs right now (in fact, there's a 2-bedroom just up the street from us that's advertising at about $1000).