[Adult Swim] has put up a FMA game on their website. It's called "Fullmetal Alchemist: Iron vs Flame." It looks similar to the FMA GBA game but more simplifed. Basically, you go as Ed and Al and hunt down chimeras (renments of Tucker's research) that are are running loose in the countryside. You need shockwave and probably high-speed internet to play it properly.
I only gone as far as the second level. Damn chimeras...>_>;