I would credit whomever first pointed out this SportsFaction article, but I can’t remember. The article discusses how to use two tools – SopCast and TVUPlayer – to watch online the NFL games not aired in your local TV market. The article also links to the Streaming NFL Games blog.
I won’t vouch for the legality of using such services, and I’m sure the NFL, with its draconian, fan-agnostic broadcast rules and policies, won’t like the use of such services. Use at your own risk. Or, considering the way the NFL seems to be forgetting its fans, feel free, as SportsFaction says, to “Go fly a kite with a hole in it.”