If you or anyone you know are interested in taking advantage of the Homebuyer Tax Credit you need to have a signed purchase agreement by April 30, 2010 with the exception of Armed Service, Intelligence & Foreign Services who were out of the country in 2009. They have an additional year. http://www.realtor.org/press_room/news_releases/2009/11/armed_services
This tax credit also goes up to $6,500 if you have owned your current home and lived in it for 5 years: sell and buy another one. The income limitations are: adjusted modified income to $125,000 for single filers and $225,000 for joint filers.
Keep in mind this credit does not apply if you by a home from a relative.