Here's a general introductory white paper found on http://www.m4if.org/. It covers the basics of mpeg-4, its application to video, interactive tv, pvr, and differences between mpeg-2 and mpeg-4. Since V* will be heading in that direction and we hear a lot about it will be good to get a general idea of the technical aspect.
http://216.120.249.94/voom/pdf/m4-out-20027.pdf
http://216.120.249.94/voom/pdf/m4-out-20027.pdf