I was a bit hasty with my last post.  The Nielsen//Netratings report for December search engine market shares in the USA was published at pretty much the same time, and shows a slight improvement for Google:

• Google Search - 50.8%
• Yahoo! Search - 23.6%
• MSN Live Search - 8.4%

The remaining search engines duke it out for the 17.2% that's left.

The number of searches remained about the same, at just under 6 billion. Remember, these figures are just the the US market. Your mileage may vary.