New edition of the U.S. Government Manual

The 2006-07 edition of the US Government Manual is available at the GPO website

The manual "provides comprehensive information on the agencies of
the legislative, judicial, and executive branches. The Manual also
includes information on quasi-official agencies; international
organizations in which the United States participates; and boards,
commissions, and committees."

It is broken down into various sections, avaiable in text format or PDF.