FRDS - "Googlebot" should do it for Google (Full User Agent string is "
Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)")
I believe there is some fine print on Google somewhere saying you must dispaly the same stuff to them as you do to regular visitors, it may be worth investigating, although I wouldn't think doing things like removing ads and welcome blocks etc whilst keeping the content the same would be an issue? Make sure you check this