Thanks reason for asking and not googling is exactly the above, ie buy here, no it's not that one, its this one coming soon etc etc.
Ao it's made by different people or something is it on the iPad? I (he) was hoping they'd mix/sync. What's the version coming in Dec? from where/who?
I understand there is other places than MAS for software, it's easier to buy from there that's all, doesn't have to be though
He was joking about December, although that didn't seem to catch. Basically just poking fun at your classification of "for iMac" when, in reality, if it works on one kind of mac it will work on them all.
In any case the iPad version (Minecraft pocket edition) is made by the same people (Mojang) that mac the mac / PC version of the game. Same with the xbox 360 version. Basically Mojang makes all of them.
Unfortunately, as far as I know, there is no way to "sync" accounts between different versions. Because the game itself is different on all versions (especially the pocket one) it would be impossible to code and have one world playable on all versions.
In any case, the link posed in the first reply is the official minecraft site. It is the only place to legally acquire the game since, technically, you buy an account and when signed in you can download the game itself.