Harmonix Lead Designer Dan Teasdale revealed new features and fixes for Rock Band 2 via a software update. Besides adding the long-awaited Rock Band Network Audition Mode, which will allow players to upload created songs, there is now background downloads, sort by stars, and wireless microphone support.

 The update is available now for Xbox 360 and "soon" for PlayStation 3. Harmonix says the delay has to do with the PS3 architecture and specific fixes for that version. There is no mention of an update for the Wii or PS2 versions.

Here’s the entire list with details:

    * Rock Band Network Audition Mode: Available from the "Extras" menu on Xbox 360 versions of Rock Band 2, members of the Rock Band Network can now upload songs from their PC’s and audition their songs using our suite of song audition and testing tools. Currently in closed beta, the Rock Band Network will welcome authors to open beta in the coming weeks! Find out more at http://creators.rockband.com

    * "Sort by Stars" in Quickplay: If you hit the "Sort" button on the Song Select screen, you’ll come to a brand new sort that orders songs by the star ratings that you’ve achieved on each song. Each star rating gets a category, as well as an "Unplayed" category for songs that don’t have a star rating recorded. Finally, you can record your progress towards gold starring every song in your library!

    * Background Downloading in the Music Store: Purchasing songs from the Rock Band Music Store now no longer requires you to wait for a song to download before you can download another song. You can now queue up downloads to your heart’s content, which is going to be incredibly handy with some of the amazing DLC that’s coming out over the next few weeks and months.

    * Xbox 360 Wireless Microphone Support: Rock Band 2 now supports Xbox 360 Wireless Microphones, like the Lips microphone. Finally, you can now have a fully wireless Rock Band experience!

    * Chord HOPO improvements: If you’ve played The Beatles: Rock Band, you’ll notice much more robust handling of chord hammer-ons and pull-offs. This patch implements those changes in Rock Band 2 to provide a more natural chord hammer-on/pull-off experience.

    * Velocity Sensitivity on Ion Drum Kits: Ion Drum kits now support velocity sensitivity in both drum fills and Drum Freestyle mode.