I don't think newspaper endorsements really matter that much anymore unless they're really surprising. But it's worth keeping track of some of them.
Obama got the Kansas City Star today. I really have no idea of the Star's general leanings. Kansas City is, like many mid-American cities, a Democratic-leaning (but not socially liberal) urban area within larger pretty heavily Republican surroundings. Given that Missouri is neck-and-neck, I could imagine this endorsement mattering a little.
The estimable Greg Mitchell at Editor & Publisher keeps track of newspaper endorsements here. It's interesting reading for sure. Obama has 57 papers with 7 million-plus total circ, while McCain has 16 with 1.5 million.