SMedia
SMedia Glamo 3362 is used in eg. Openmoko's Neo FreeRunner.
2D kernel driver: http://git.openmoko.org/?p=kernel.git;a=commit;h=911c6fab17f81ea2fdc6ad5e6173ce72bfe01ec4
2D accelerated X driver: http://git.openmoko.org/?p=xglamo.git;a=summary
Data sheet: Only available under NDA, not likely to be available otherwise. Some hacks done without the NDA.
Note that choosing Glamo has been accepted as a bit of a design mistake, both from performance point of view and openness point of view (3D part). So future Openmoko products will not feature the chip, but the currently (2008) selling Neo FreeRunner (GTA02) does have it and could be usable for 3D acceleration and other accelerations. Known limitations include (?) maximum framebuffer size of 512x512, which effectively excludes FreeRunner's default 480x640 out - so eg. the alternate resolution available, 240x320 (QVGA). is fine.
DRI2/KMS enabled stack (including attempts at 3D) work-in-progress here