I recently saw that TF2 has updated its code so it doesn't run slow for the Mac OS X 10.6.4 update (which I was holding off on doing since I wanted to play TF2).
I just saw that I need to restart Steam because of an update which included this:
OSX: Fix several memory leaks
OSX: Fix copy/paste resulting in extra random string data
Sorry for the confusion on the real question. The question I am asking is: Do I have to do/download anything to see if the so called TF2 update for 10.6.4 is on my machine? They have told us before that we shouldn't upgrade to 10.6.4 yet since it was buggy with TF2 (graphics problem) so now that they have advertised it and I have upgraded to 10.6.4, is the update already on my machine or not? I checked the Steam update log as mentioned in one of the answers, but I haven't seen any trace of their 10.6.4 fix.
Another edit: Apple finally released an update for portal and tf2 specifically. Here's a screenie: