The Battlefield 2 mod tools were originally intended to ship on or before the games' actual ship date, obviously that didn't happen but it seems that we are actually nearing the release.

One of our long time members, and keen tinkerer Maz, recently emailed Lawrence Brown, the Battlefield Mod Support Coordinator and received this response.

Actually, there should be an update on the community update section of
the EA site soon. It's gone into final testing and should be out in the
next few days.

Sorry about the wait, but we wanted to make sure it's all working
correctly before releasing it.

So it' seems that custom maps and mods can get started properly soon, I'd expect to see the first few maps very quickly.

** Update **
There's confirmation in the bf2 community update.