I usually just rely on the nightly repository to stay up to date with the latest avidemux brew.
But the windows binaries there are still at revision 2.6.7.
In case anyone is looking for this latest milestone version.
It was uploaded by Mean to http://sourceforge.net/projects/avidemux/files/avidemux/2.6.8/
Also at http://developer.berlios.de/project/showfiles.php?group_id=1402&release_id=19537 (_v2.exe is the one)