Linked by Thom Holwerda on Wed 9th Jun 2010 21:31 UTC
WebM support has been added to Firefox trunk. "Today I landed Firefox's WebM support on mozilla-central, our Firefox development branch. It should appear in nightly builds from tonight onwards. Firefox should build with WebM support without needing any extra changes to your build configuration, unless you're building on Win32, where you'll need to have MASM installed in order to compile libvpx's optimized assembly."