While just typing random URLs into the bar, I found http://www.mccainpalin08.com and http://www.mccainfiorina08.com , which are both parked at Godaddy. They trace through Internic Whois to Godaddy as well... just for fun, I suppose.
www.mccainpalin08.com was created in Feb. 2008 - rather insightful, don’t you think? However, www.mccainfiorina08.com doesn’t yet show up on Internic Whois...
Those are the only two I have found so far!
Also parked at Godaddy - http://www.mccain-hutchinson.com . Listed as created Feb 2008, like the Palin one; VERY prescient!
Interestingly enough, John McCain’s official website appears to be hosted by Godaddy.com...
I was also surprised to find that http://www.mccain-ridge08.com mirrors the official McCain website, but does not appear to be hosted through the same service.