The existence of a whittled down version of Planet Puzzle League for Nintendo's DSiWare download service shouldn't come as a surprise—unless you forgot Nintendo already released that miniature version of the game in other territories, as I did.
Thankfully, the ESRB is here to remind us that Nintendo of America will bring the game formerly known as Chotto Panel de Pon stateside. And hopefully soon. Like today's release of Brain Age Express, Puzzle League Express will offer a more bite-sized version of the classic tile swapper.
You may remember (and love) it under its other names, including Tetris Attack and Pokemon Puzzle League. If so, keep an eye peeled for the DSiWare mini-release.