I have no idea what cost would be appropriate for this ability. In Limited, it's not very good, but imagine it in 2HG or Archenemy.

I want each player to be able to choose what their getting. Something like Hive Mind would be nice, but all transfers have to be simultaneous.

I think this wording would work:

> Each player chooses a permanent he or she doesn't control. Then each player gains control of the permanent he or she chose.

If you want the targets to be known beforehand (which is generally sensible), the wording needs to be a bit more fiddly, similar to Evangelize or Arena:

> For each player, that player gains control of target permanent of that player's choice that he or she doesn't control.

One note on this: because this card requires all its targets to be distinct, turn order matters: the first player to choose a permanent bars anyone else from choosing this permanent.

The caster gets first pick, right?

Yes. Hmm... possibly except in cases where this is cast on someone else's turn, via Vedalken Orrery or other oddness.