I am also interested.
And also I find it pretty shitty that most altcoins exclude mac users.
Most only offer either a win or a linux client. Mac is everywhere nowadays so this seems a bit unfair.
If we want decentralization addressing this problem is part of it, too.
I am using BitMinter to mine with on my Macbook Pro with Snow Leopard. So far it is not overheating, tho the hash rate leaves a lot to be desired.

I am only getting around 7mhps no matter how I tweak it.