It's a Universal film so you'd expect it to be HD-DVD exclusive but Spielberg doesn't want any of his films released on HD-DVD.
Last year, universal advertised Jurassic Park as coming soon but were made to drop it by Spielberg and issue an apology. Spielberg has gone on record that he supports Blu-Ray and the only one of his films out in HD is on Blu-Ray (Close Encounters).
Jaws will remain exclusive to VHS and DVD until Universal support Blu-Ray. I don't know what happens when Indiana Jones and the Kingdom of the Crystal Skull is due out. It's Paramount so HD-DVD but directed by Spielberg.