The devices will support an open platform -- which means they will play a variety of music formats such as MP3 and Microsoft's WMA, providing more choices for downloading and managing music and video collections online.
Sony added that it would pull the plug on its Connect Music Services, which distributes music in Sony's proprietary ATRAC audio format in North America and Europe. Specific timing will vary, but the move will not occur before March 2008.
Sony said the models' battery life allows up to eight hours of video playback for the NWZ-A810 series, which will sell for between $140 and $230. Battery life will be more than nine hours for the NWZ-S610 series, with prices ranging from $120 to $210.
The announcement comes amid speculation that Apple will next month introduce new versions of its ubiquitous line of iPod media players.