|This is not the new 'HD' Halo... Obviously.|
As for new features, supposedly the new re-do will have new artwork to put it in line with later releases in the series, will be in HD, will have 3DTV compatibility, and will have more current Halo control configurations. It will also feature online multiplayer and co-op. What it will not feature is the same engine that ran last year's Halo Reach.
As far as official announcements go, there's nothing yet- but between this and the second mystery Halo title being developed you should expect a Halo showing of some kind at e3 this year.