And you can buy it of Steam for $14.95(US) which is like $19 Australian.
It's RoboBlitz, and from various reports, the Unreal Engine 3 editor is included, as well as Kismet (the scripting tool which allows you to create complex games. Mark Rein said that you could make a Tetris game with it, for example).
Anyway, Unreal Tournament 2007 hasn't been given an official release date yet but I'm assuming that it's still a while off yet, so this is a really nice and relatively inexpensive way to get accustomed to the Unreal Engine 3 in the meantime. The RoboBlitz developers are putting up a modding wiki soon which will be very handy indeed. More details in their forum.