Miley Cyrus is either taking one for the team by agreeing to a fourth season of Hannah Montana or not-so-humbly fulfilling the terms of her multi-year deal with Disney Channel. The singer's father, Billy Ray, told Access Hollywood that he gives "a lot of credit to Miley for taking it another year. She didn't want it to just end with whatever was the last episode we did. She wanted it to build to where there's a moral to the story, to where it doesn’t just end and go away and that’s it. She wanted there to be an official ending to Hannah Montana."

But the singer-actress also had a contract to fulfill; a Disney source told EW that the network already had an option on Cyrus, 16, for a fourth season and simply decided to exercise it.

http://news-briefs.ew.com/2009/06/miley-cyrus-season-four-was-her-choice-dad-insists.html

Ohh ok. If a season 4 is coming what will that be about them?

That's pretty nice of her to make sure there is a real ending to the series and not just leave viewers hanging. She obviously likes doing the show and even if she is obligated to the Disney contract she could have easily had the show canceled. I'm sure she doesn't need the money, but she seems to be loyal to her fans.