I have upgraded to ICS on an i9100, from GB. Both of these provide wifi tethering by default. Under GB many of the widgets available could toggle the wifi tethering on and off - a simple switch.
These toggle widgets do not work under ICS on this device - either they do not work and error, or they open the settings / Tethering and Portable Hotpot page rather than directly switching the status.
If I look at the shortcuts available in Settings, this is as deep as it goes - even with AnyCut or llama intents. Does this mean it simply isn't possible to get a wifi tethering toggle any more, or is it possible there is an unadvertised intent that will trigger it?