Last Friday I released v1.11 of the SM2496 Software Development Kit under the GPL v2.0 License. The SM2496 is a DSP module (essentially a soundcard) for the Handspring Visor PalmOS devices. This SDK includes complete source code for a couple of PalmOS Amateur Radio packet and APRS applications, and the full source for the TI DSP 1200bps and 9600bps modems.
An interesting tie-in to Linux is that the modem code is based on the Linux Kernel Soundmodem driver software by Thomas Sailer. The usefulness of his work inspired us to release all of our software as GPL in the hopes to attract more developers to use the SM2496 platform.
With a sufficiently motivated programmer the SM2496-16 (160MHz DSP with a MMC card slot) could be made to play and possibly record using the Ogg Vorbis format. The only reason that I haven't done this myself is the lack of time. We are current beta testing MP3 play and record on this platform and plan to release a MP3 player/recorder later this year.
The SDK is available from the Shine Micro Software Page
There is also a press release for the SM2496 here at the SM2496 Press Release Page
Shine Micro, Inc.