You can find webmdshow-0.9.8.1-20100608.zip on the downloads page:
http://code.google.com/p/webm/downloads/list
http://code.google.com/p/webm/downloads/detail?name=webmdshow-0.9.8.1-20100608.zip
http://webm.googlecode.com/files/webmdshow-0.9.8.1-20100608.zip
The source code is also available as a separate download:
http://code.google.com/p/webm/downloads/detail?name=webmdshow-0.9.8.1-20100608-src.zip
http://webm.googlecode.com/files/webmdshow-0.9.8.1-20100608-src.zip
You can also download the sources directly from the git repository:
git clone git://review.webmproject.org/webmdshow.git
Here are a few of the changes in this release:
Fixed bug when webmmux filter not connected to file writer.
VP8 encoder filter now has a preview pin.
VP8 encoder filter now supports FORMAT_VideoInfo2.
VP8 encoder filter now allows you to set config on-the-fly, while
graph is running.
VP8 encoder filter added support for spatial and temporal resampling config.
Regards,
Matt