I am currently in an online franchise for Madden 10 on PS3, and we are in need for some new owners. It's a solid league and we usually advance every 4-5 days. The franchise is in Season 2 in the Super Bowl, which has the Lions(!) playing the Pats, so if you are interested we should be doing the rookie draft on the 21st after some members get back from a trip. There is a website for the league that is pretty nice. Link here.
Not sure about all the open teams exactly since EA won't let me check but the ones I know of are the Bucs, Bills, I think the Chargers, Dolphins, Chiefs, Jaguars, Seahawks, Browns. Not sure if there are more, but that should be most of them.
We don't want any cheap players, and we play with some rules to make sure the game is played the way it should be played. We will also be continuing this franchise in Madden 11, I believe.