Revision to my previous post about the settings change not working. It does work.
In a post last night, I said I had tried the settings change that Dapheel had posted about and that it didn't work.
After that post, I decided to reboot the phone to see if the setting change would be activated after a reboot. It was. I let the phone sit all night and there was no longer battery drain. When I activate the phone from a dormant state, I can see the wifi activating in the top of the screen. So, at least on my S2, I would say it has fixed the problem. It does seem to take a few minutes, or so, for the wifi to disengage when the screen is turned off, however, but not a real big deal.