This link takes you to the website of Dr Steven Holland, a GI doc in Chicago.  His local support group has compiled a rather extensive list of commercially available gluten-free foods. 

Use this site at your own risk (although I have looked at it & it's quite good). 

The list requires Acrobat Reader.  If you don't have it you can get for free from Adobe at:  www.adobe.com

They also offer a free reader for palm OS. 

Dr Holland's website including GF food list (go to bottom of the page)