In an interview at All Game Radio Kyle "Pezman" Peschel FOX Interactive's PR Director, had some good news for AVP fans.
Fox are about to release the source code for AvP Gold Edition and AvP's Engine. They will also be releasing official editing tools for Aliens vs. Predator.
These tools to be released are the real thing. They are the tools used by Rebellion to create the game. The down side is that, as usual, no support will be offered, but this is unlikely to deter fans of the game, determined to create those Mods.