The erstwhile Gamma-Ray Large Area Telescope (GLAST) has today received a new name: Fermi. More officially, it is the Fermi Gamma-Ray Space Telescope, one of the flagship orbiting observatories like the Hubble Space Telescope and Spitzer Space Telescope. Fermi studies the sky at very high energies, an area of science that I don't know much about. It is therefore quite fortunate that I can point you to Phil Plait for a more knowledgeable explanation than I can provide! He also has one of the Fermi images that were unveiled at a press conference today, a view of the entire sky at gamma-ray wavelengths.