[davidw]

According this article at Phoronix it seems that video acceleration with ATI graphic cards is now possible but with limitation to MPEG-4 AVC (H.264) and WMV9 (VC-1) formats.
The packages are available at Splittet-Desktops.

I hope that in the next months this feature will get as usable as Nvidias VDPAU in XBMC.

[prae5]

I wouldn't expect it too soon. The patches for supporting it haven't been accepted into ffmpeg yet. So until that happens no potential support for xbmc.

Once in xbmc if there is a dev who wants to do it, then it may get added - but until ffmpeg adds support for it it wont happen.