Just wondering if it will be available on MAC for steam?

Doubt it, few are the games that end up being released for the mac, as it is a very niche market.
There's nothing stopping you from using Bootcamp though...

I have paralles, I just never tried it for gaming? I have a Mac Book pro with dual nvidia video cards etc. Anyone have any feedback>?

It hasn't been announced for Macs and there hasn't been any evidence that this is being considered, so it does seem unlikely.

Since bethesda basically bought id for id Tech 5, exclusive to only Bethesda now, and according to Carmack can do multi-platform compile with the press of one button it would seem like a complete no brainer not to compile for Mac and sell on the Mac App store, unless Bethesda has a hate on for Mac despite record breaking quarter after quarter of Mac sales. Value, Blizzard certainly see the value and profit of serving a "niche market" and they will certainly get my business and support.

Cross over also works quiet well

You might want to get a PS3, 360, or a PC because I don't think MAC will be getting Brink. Sorry....

Well, while I do believe that Macs aren't for gaming, (rather for those artsy hipsters), Brink will be available for purchase on Steam. However, Macs are not listed, so I'm guessing you might want to go out and buy yourself other means.

Brink isn't using id tech 5, I believe id tech 4 is the foundation they started with (maybe even id tech 3?) but the engine has been added to and modified to the point where no line of code has been untouched. It's possible that during this time they dropped Mac support, but whatever the case I don't believe I've ever heard Splash Damage mention Macs in regard to Brink and that suggests to me that no Mac port is planned. I could be wrong, moderators are not employees and we aren't privy to unannounced information (and nothing I say should be considered at all official).

In regards to id tech 5, RAGE has been announced for OSX and it makes sense that other games using this engine will as well but this is a more appropriate topic for the Community Discussion forum as it does not pertain to Brink.

It would be unfortunate if Bethesda didn't do a Mac port, both SD's previous games have Mac ports and I believe all of id Software games have had Mac ports as well

I do own 360, but fps are way better on pc platform, and mac's are far more stable a platform so I wanted to experiment a bit I guess you could say.