Google Analytics has launched asynchronous tracking. What this means is that the pages load faster and the analytics piece of javascript loads without blocking the rest of page from being rendered. Earlier this was not the case, hence we had to insert the analytics script code just before the </body> tag in your pages.

The following web page gives details on migrating to the new async code, the old way of tracking still works but in my opinion the soon one migrates to the newer code the better.
http://code.google.com/apis/analytics/docs/tracking/asyncMigrationExamples.html

More Information on this from google and steve souders:
http://googlecode.blogspot.com/2009/12/google-analytics-launches-asynchronous.html
http://www.stevesouders.com/blog/2009/12/01/google-analytics-goes-async/