Pokemon Battle is online in Japan. I looked all over and the first review of the multiplayer online experience I found was from IGN.
"The actual online play also has some problems, primarily with lag. Every menu selection seems to be accompanied by a couple of seconds of lag."
This dosen't concern me too much, considering that Nintendo has a few months to iron out the flaws before it is released in the states.
If anyone reads any other reports, please leave a link to them here.