Japan has had 3DS retail game demos on the 3DS eShop for quite a while now, but tomorrow they'll debut in North America. The first demo to be released will be the one promised by Capcom for Resident Evil: Revelations.
Game demos in Japan come with a 30 play limit, which you can likely expect to see carried over to the West. Really, if you like the demo enough to play it 30 times, maybe buy the retail game.
Revelations is only the beginning, as a demo for Mario & Sonic at the London 2012 Olympic Games drops next week on the 26th and demos for Metal Gear Solid: Snake Eater 3D and Rayman Origins are coming at an unspecified future date.
