lammert - 6:35 pm on Mar 10, 2010 (gmt 0)

You can use a server header checker to see if URLs from the old domain properly redirect to URLs on the new domain with a 301 redirect code. There is a server header checker available here on this board in the subscriber section, but you can also use the "Fetch as Googlebot" option in Google's Webmaster Tools or use a server header Firefox extension.

If the 301 is correctly returned, it takes some time until the search engines and Alexa have processed the move of all the URLs from the original domain to the new.