Film Score Magazine has a video interview with Michael Giacchino, the composer of Cloverfield's closing credits overture "Roar!". Giacchino was surprised by the demand for the score, but is said to be working on releasing it in some form soon, presumably in time for the DVD release.
ScoreKeeper of AICN reports that "the original composition was thirteen minutes long while the version which ended up in the film was edited down to eleven minutes. [Giacchino] concludes by saying the version they’re going to release will be the full thirteen minute work."
* Thanks to Michael L. for the update!