I'm a mac user. There, I said it.  
 
I have never owned a PC capable enough of running anything serious game-wise and I've been using a Mac pretty exclusively for the last year or so.  Aside from dipping into the classic Blizzard catalog I've been pretty shit out of luck getting much off-console gaming done. I know, I could bootcamp and work around that, but I'm far from tech-savvy and honestly, I've never really felt that motivated to make that focused of an effort, just I could game on the PC.  
 
Then the kind folks at Valve answered the call of all of us pretentious OSX gents: "We'll let you guys play our stuff and use our service, straight up" 
 
I was/am a huge fan of TF2 and Left4Dead, so needless to say I was fully stoked at the news. I can enjoy them the way they were meant to be (and in TF2's case, I can finally play it again, since console-side that game died a few months post-release). 
 
So whenever May 12th is in Valve-time, I'll be making the plunge. This has left me with a burning question, however: Will I be able to run Garry's Mod?  
 
I know that Valve's main Source catalog will be represented, but does making Source run on OSX also apply to Garry's Mod, and I guess modding in general. 
 
Again, I'm not a tech savvy guy, so this might be an obvious thing.
 
....I just want to make a bike gun of my very own. Something to be proud of, send home to the folks and show 'em I made something of myself with this fancy college education.

 It depends on whether they port it or not. They are probably going to use Cider to port the existing Valve games to OS X, and all the Valve games released after May 12th games will run native on Mac.  

"  It depends on whether they port it or not. They are probably going to use Cider to port the existing Valve games to OS X, and all the Valve games released after May 12th games will run native on Mac.   "

I would think they they would put the added work into porting it eventually, if not immediately.
 
It seems like it's one of those things that has a lot of drawing power in it, especially for those who haven't had the opportunity to use it previously.

As of Tuesday Garry made a blog post saying that he's working on it - he's got the engine code, and it's compiling, so at the moment it's going through bug testing (which those guys are pretty thorough about given the monster that is GMod). The release date is "when it's done" but it will probably end up being one of the sooner Mac releases, considering how many games Valve has to filter out over the next few months.

I really hope Mac users latch on to this when it comes out because I feel like it would be right up their alley (also a Mac user for the record).

http://www.garry.tv/?p=1745

Don't worry duder. Even if they don't end up porting it, you can always just use bootcamp like this guy.

And thus, it has been ported :)