This one's going to confuse people, if only for the reason that there are a few Astro Boy games on the market now; one by published by Sega and developed by Treasure (known for Gunstar Heroes and Gradius 5 alongside a number of other classics) on the Game Boy Advance, and the others based on the movie that was just released in the US today.  All of those were published by D3 for PlayStation Portable, Wii, Nintendo DS, and a port of the Wii game on PS2.  Here's where things get really confusing; Sega also released an Astro Boy game for PS2 back in 2004 that was developed by Sonic Team (guess what franchise they're best known for?)  The games based on the movie were just released, so I'm not covering those yet, unless they hit bargain bins.  From what I understand, they're all side-scrolling action titles that play somewhat like the 2004 GBA game.  Today, we're gutting the 2004 PS2 game, so that no one gets confused when their kids see the movie in theaters and want to play it on their PS2 (You know, since you won't buy them a Wii.)