From what I've heard, Mini's aren't in the US yet, they will be in a month or two. They don't have ANY games (wah), they're only two-thirds the size of a Connection. No connecting feature, though. All you need to do is feed it meals or snacks and voila! they're happy. Mini's are supposed to be more of a decorative keychain than a fully functioning Tama...most of the colors are targeted at girls, it seems.
I already saw some USA mini Tamagotchis on ebay today, so I guess they will be out in stores soon h34r: Mimitchirocks is right about the features. I've got a Japanese Tamagotchi mini and all it need is to clean up the poo, feed it and put it to sleep. It doesn't require much attention and it has got less characters than the first Tamagotchi. But I liked to play with it, it also has got secret chracters.