Maybe ever.
DICE won’t provide mod tools for new super-creation Battlefield 3 at launch.
The developer explained to Game Informer (via NeoGAF) that the new and much hyped Frostbite 2.0 engine makes everything more complicated; releasing mod tools would take a lot of work. And does DICE want to focus on that or making the game?
Nevertheless, DICE confirmed that PC will be the lead platform for Battlefield 3. This decision manifests in 64-player online PC battles. DICE didn’t specify how many can fight online on consoles, although US shop-chain Best Buy reckons the number will be 24 (thanks, VG247).