The Form 477 Database: See http://broadbandbreakfast.com/tag/form-477
The Form 477 Database is the most complete collection of broadband data available, and the FCC has it in its possession right now. The FCC should publicly release this database so that others may build on it.
The FCC report DOC-296239A1, "High-Speed Services for Internet Access: Status as of December 31, 2008", shows tract level data in the GIS maps. It seems unjustifiable that these data should not be released raw given that these are already presented, albeit in an obfuscated manner.