AOL Music has a streaming preview version of the full CD Soundtrack for Pirates Of The Caribbean: Dead Man’s Chest. I can’t provide a direct link to the CD, but it’s one of the choices today at least.
There are the familiar themes of Curse of the Black Pearl in there, but Hans Zimmer has come up with plenty of new and intriguing music for this version. In particular there seems to be a dark playful mood to this soundtrack. It does sound very much like the middle of a trilogy.