@spendius,
The teams operate under an umbrella organization called the NFL. There is a boss (commissioner) and a board.
The TV networks (CBS, NBC, ABC, Fox, ESPN) bid for the rights to broadcast packages of games. The NFL gets a shitload of money from the networks which could, in turn, sell advertising during the games.
The NFL decided that they could set up their own network, the NFL network. They could start out by broadcasting just one live game or so a week, starting with the Thursday night game, filling the rest of the week with replays of old games and talking heads who would probably appear for free in order to be on television. Fans, if they wanted to see that one live game (like tonight's), would have to subscribe to the network.
The plan, I think, is that the NFL network intends to cut the traditional networks out of the picture totally over time.
That's what I think, but I don't even have a tv. So what do I know?