During Apple's keynote speech at the 2009 Macworld Expo, Phil Schiller, senior vice president of worldwide product marketing, announced that the company would be removing digital rights management from all of the music offered in the iTunes Store, and would implement a new tiered pricing system (for more details, see "Apple Moves to Unprotected Music, Tiered Prices", 2009-01-06). Apple's FairPlay DRM limited music sold through iTunes to recognized devices. On the day of the announcement, 06-Jan-09, Apple removed DRM from 8 million songs in iTunes, but that still left an additional 2 million songs to be switched over. Apple has now made good on its promise in full by removing DRM from all music in iTunes.
In addition to removing DRM from music sold through iTunes, all songs now use 256 Kbps AAC encoding, which was found previously only in the subset of Apple's catalog known as iTunes Plus. The previous bit rate, 128 Kbps, will no longer be available. Users will also have the ability to upgrade previously purchased music to this higher quality DRM-free format at the rate of $0.30 per song and $0.60 per music video. To upgrade your existing music, click the Upgrade to iTunes Plus link on the iTunes Store front page.
Reports on TidBITS Talk indicate that the switch isn't 100-percent complete, with some songs having been removed from the iTunes Store (possibly because Apple couldn't acquire resale rights for DRM-free versions) and others simply not yet available in iTunes Plus format. After upgrading, you can determine whether you have any of these tracks by creating a smart playlist that looks for "Kind contains protected" and "Kind contains audio".
Lastly, Apple has implemented a tiered pricing system. Previously all songs were available at the flat price of $0.99, though purchasing full albums could sometimes result in a discount. Now, songs are available at $0.69, $0.99, or $1.29. Apple has not commented on how exactly song prices are determined, though Schiller did note during his presentation back in January that there are more $0.69 songs than $1.29 songs.