Benjamin Smedberg recently discussed the motivation for splitting Firefox into multiple process, so I won't recap that here. Instead, I want to demonstrate what we've accomplished so far. The video below shows our nearly Phase I-complete browser. (Back and Forward don't work yet, but are relatively easy to add.)
Multi-process Firefox, coming to an Internets near you < Chris Pitchin’ Hey

Chrome-style. This will be a great change IMO.