Eidos appear to be continuing their love affair with Tomb Raider DLC and have just announed that Tomb Raider Underworld will recieve it's first of two DLC Packs on February 10th exclusive to Xbox 360.
According to the official website "Beneath the Ashes sends Lara back to the remains of Croft Manor where she uncovers a massive series of never-before-seen caverns and age old crypts used to protect and hide a deadly source of power. The pack will also contain six new costumes and deliver an additional 125 achievement points."
As I said before this is the first of two planned DLC packs the second 'Lara's Shadow' also an Xbox 360 exclusive has been confirmed for March 10th. No price has been mentioned yet but I would not expect this to fall under the 1200 MS points barrier.