The Nations At War team has released version 3.9 of their Battlefield 2 conversion. This new release includes several new maps, new vehicles, new weapons, and significant tweaks and changes to existing content. I could write them out, but it would probably better for you to go right to the Release Notes for the full listing.
One immediate improvement is the availability of map packs for this mod as previously all maps were downloaded individually. You can find links to download the 3.9 client, the client with map pack 3, or any of the map packs at the Nations At War website.