You can downgrade your 4S to 5.0.1 and jailbreak if you have a 5.0.1 SHSH for your phone. If you jailbroke the phone while it was still on 5.0.1, the SHSH was probably automatically saved in Cydia. You can use
TinyUmbrella to check and see if it's on file in Cydia or saved to your computer. If it is, you can follow
this tutorial to downgrade and jailbreak. If it isn't saved, you'll need to wait for the 5.1/5.1.1 jailbreak, which may be available in a few weeks.