Here it is, the official announcement for Jedi Knight 3, or rather Star Wars Jedi Knight: Jedi Academy, as that is the official title. LucasArts has also opened the official site and you can find screenshots here. Thanks to The International House of Mojo.

Star Wars Jedi Knight: Jedi Academy begins shortly after the conclusion of events in Star Wars Jedi Outcast. Players create a Jedi apprentice character and join the Jedi Academy on Yavin 4 to learn the ways of the Force under the tutelage of Luke Skywalker and Kyle Katarn. While the young apprentice embarks on various missions to hone their skills and abilities, a mysterious group is discovered creating havoc throughout the galaxy. Until order is restored, the fate of the Jedi Academy - and the future of the Star Wars galaxy itself - hangs precariously in the balance.
While players will be able to accomplish more by using the lightsaber in Star Wars Jedi Knight: Jedi Academy, they also will have a variety of weapons - new and old - at their disposal including a blaster, blaster rifle, Wookiee bowcaster, Imperial repeater, and a Destructive Electro-Magnetic Pulse gun.

Jedi Academy will be released this fall on PC and Xbox.