This is a question that's discussed pretty frequently on the Starwood forum. Here's some reading that might be of interest to you (the first one in particular):

http://www.flyertalk.com/forum/showthread.php?t=175862
http://www.flyertalk.com/forum/showthread.php?t=175443
http://www.flyertalk.com/forum/showthread.php?t=169318
http://www.flyertalk.com/forum/showthread.php?t=174615

Are you an elite member with Starwood Hotels?