Chill...nobody lives here, and we all have lives to live.
At any rate, any application that is set to check for updfates automatically will invoke the connection. So will IM apps. Shozu, which is included with the Omnia can even cause this. You can search for a GPRS disconnect program, or use a regack to time out the connection early. Additonally, I suppose you could change the "dial in number" from #777 to something else so it won't connect. I'd reccomend the timeout settings, though.
Just an FYI--I've never had the EVDO kick me off my wireless network. Both can co-exist at the same time.
Give this a shot. I've not tested it, so its your problem iof your phone dies from it
http://www.mediafire.com/?909nmehimm0