Besides watching craigslist and ebay, you could check out the following two places in Chicago to see if you can get the bike back:

Ashland Swap-o-Rama @ 4100 S Ashland Ave, which is open Saturday and Sunday; and the Maxwell Street Market, which runs near Des Plaines and Roosevelt on Sunday.

Both are pretty notorious for reselling stolen bikes in Chicago. Not sure when they open, but I have heard a few stories on the chicago fixed gear board and on the chainlink board of people finding and recovering their bikes at the markets. Swap-o-rama seems to be where a lot of stolen bikes end up. If you are going to head down, make sure to file a police report and have a copy with you (if possible) to prove the bike is yours and stolen. At the very least, try to have something that proves the bike is yours. Otherwise, you may be forced to actually buy it back if you find it.