Federal Government Greenhouse Gas Registry Act of 2007 - Amends the Clean Air Act to establish within the Environmental Protection Agency (EPA) the Federal Emissions Inventory Office. Sets forth the Offices' duties, including: (1) developing and using a greenhouse gas emission inventory or other system to measure and verify direct emissions (emissions directly from a source owned or controlled by the federal government), energy indirect emissions (emissions resulting from the production of electricity purchased and used by the federal government), indirect emissions (emissions resulting from the conduct of a project or activity by the federal government), and offsets of those emissions; and (2) establishing an emission baseline for the federal government.