Where are you located? There are indoor leagues in villa park at the odeum,in hoffman estates and in palatine. Also there is indoor soccer facility at diversey and western aves in chicago.
In the winter, I play in a league at Windy City Field House, 2367 W. Logan Blvd. (near Western Avenue and the Kennedy Expwy., next to Target). On Fridays, anyway, they seem to have many leagues at a variety of skill levels. You could probably go over there or call and see how to sign up.
there are also south suburban leagues in Frankfort, Darien, and Dolton but its during the winter (Nov-Apr)
It might be a bit far, but if you are out in the Northwest Suburbs, Kits in Lake Zurich is a really nice option. They keep the place in good condition.