Back in March one of the proposals this year was to create VP8 support over VDPAU in Gallium3D. Originally this began as an H.264 VDPAU state tracker and then targeting WebM or Theora instead. In the end the GSoC proposal was for VP8 in Gallium3D via the VDPAU state tracker. However, the proposal was not accepted by Google due to technicalities.
Even with not being accepted as a GSoC project, the French student, Emeric Grange, is still working on VP8 for Mesa support. Ivanovic mentioned yesterday the existence of this Git repository: mesa-vp8.
The mesa-vp8 repository was created by Emeric and is the place where he's doing this VP8 work that in turn is based upon the recent Mesa pipe-video activities. The most recent commits are just 15 hours old. The VP8 format support is being added inside the VDPAU (NVIDIA's Video Decode and Presentation API for Unix) state tracker, but so far it doesn't appear functional. Hopefully that will change this summer.