Chris Anderson of TED is maintaining a site with resources to keep up to date on the spread of the H1N1 swine flu. Click here to go to the site. 

This Google mashup tracks the spread of the virus around the world.

Here is a link to a Google Mashup showing the spread of the H1N1 Swine Flu in North America. http://tinyurl.com/cywddc

May 2, 2009:  A note on this site says that it is no longer being updated.  It refers you to http://flutracker.rhizalabs.com/, where they are maintaining an updated database.