Closing Theme Song For Every Episode

Hi everyone:

I know that the opening theme song for The Hills is "Unwritten" by Natasha Bedingfield, but I am looking for the name of the closing theme song that they play at the very end of each episode (during the credits). Is it possible that the closing song is just an extension of "Unwritten"?

I think that it may be an original composition by the MTV team, but even if it is, does anyone know if I can obtain it somewhere? Or what the name of it is?

Maybe it's on a soundtrack for the show (if one exists?).... but I'd like to just get that one track if possible.

Thanx in advance!