Previously I posted the solution to some of the levels in SimplePhysics (iPhone game). The game has been updated with new levels since, and I can now present my solutions to all of the levels (including Windy City this time).
Here is the walkthrough to all of the levels.
These solutions worked for me, when i made them. If they don’t work for you, either you are making it wrong, or the game may has been updated so the solutions don’t work anymore.