Hi Goat, If you want to dive mid-week besides the boat option, we can always set up a mid-week dive/meet up at Haigh Quarry which is about 45 miles south of the city. With enough notice, we can get a decent crowd of people to come on out. Its a large quarry with quite a few attractions to keep you busy for the day and most of us are out there fairly regularly.
Haigh Quarry has full equipment rental options for you, if need.
Home - Haigh Quarry - The Place for Scuba Diving in Northern Illinois Also, if you have the cert, Scuba Emporium can rent you a dry suit if you want to go that route, at least I think they require the cert.
Home - Scuba Emporium, Chicago, Illinois, Midwest & Florida Instructor Training & Equipment Leader
A 7 mil is sufficient for the Quarry for most people (and a 5 mil for others), and I think for some stuff on the lake as well. Depends on how deep the wrecks are that you are going to see. Water temps tend to stay chilly at depth in the lake, even if the surface temp reaches 70's.
For boat charters: Windy City Divers leave out of Burnham Harbor which is by the Museums (closer to down town than anything else)
Windy City Diving.net Home Page The other options are either
N'Pursuit Adventure Charters, Scuba, Wreck Diving and Sportfishing Charters on Lake Michigan out of Hammond Indiana (30 miles away south) or Capt Dale (as previously offered)
Captain Dales Inc. out of Waukegan (30 miles away north).
Good luck to you and hopefully we can meet up at some point while you are in town.