Lame_Wolf - 6:56 pm on Oct 20, 2010 (gmt 0)
There is one SERP that I check many times per day. It normally gives results for 12.3 million. For the last few days it has shown 4.9 - 5.1 million results.
For the same Keyword, Bing states 45 million, and Yahoo states 46 million.