Tools for Looking at 990s

Everyone thinks Guidstar is the end all be all for looking up non-profits, but there are more options out there and not all of them retrieve the same data. So far I've found:

GuideStar (only 3 990s for free and they are always hounding you to become a member).
Foundation Center's 990 Finder (sometime gives different hits than GuideStar, has an ultra-handy zipcode search)
Economic Research Institute (several more archived 990s, don't seem after your money, also touts nonprofit salary research)


Here's a handy document that tells you how to read a 990.