Equi:
I have lots of Mac experience, especially with gaming. This post is going to be kind of long but I'm a huge Apple geek and you're my buddy, so I figure I owe it to you to impart some knowledge. Trust me, you'll want to read the whole thing.
I am running 10.4.10 on a MBP 15''
2.33 GHz Intel Core Duo
2 GB RAM
256 MB ATI Radeon X1600
Yes, this computer is wicked fast. It hauls ass on all games. In Trem you can bump your max_fps to 125 and not have any problems provided your ping is under 100. I have some tips for you:
1. DMG files - you seemed a bit confused about what the .dmg file was. A DMG file is a virtual disk just like an ISO. When you open it, it will mount a disk on your desktop just like a CD would mount. You can't edit files that are on the mounted disk because that data is technically not on your hard drive, but enclosed in the virtual disk. DMGs are used for a lot of Mac software, you have to download a .dmg file, open it, open the mounted disk, and then drag-and-drop the application that is in there on to your hard drive (Applications folder usually) to run it properly.
2. Boot Camp - it's ridiculously easy to use and especially if you are going to be gaming it is basically essential. I play Oblivion, Neverwinter Nights 2, and many other graphics intense games in Boot Camp and they work beautifully. It is kind of a pain to get everything set up just how you like it, but the Boot Camp assistant is fairly easy to use. Switching between your Mac and PC partitions is easy if you use Quicksilver [see below], just follow a tutorial I published here:
http://www.macinstruct.com/node/129.
3. Teamspeex - yes, it is fairly buggy but here is my experience: it works well all the time, even after leaving it running for an extended period of time. There have been a few instances where it has messed up transmitting my voice, but a quick restart fixed that problem. The main thing to worry about is that sometimes it causes a kernel panic when quitting out of Tremulous. If they are both running and then you decide to quit Trem, your screen may go black and you might have to do a hard restart (hold down the power button). I have contacted the developer about this, but I haven't noticed any damage to anythign on my computer.
4. Mac system - a few things for a newb Mac user.
A. In your Applications/Utilities folder there are a bunch of useful things. Activity Monitor is the Mac equivalent of Windows' Task Manager, although it's kind of painful to say that because Activity Monitor is so much more powerful and easier to use. Check there for system stats and to quit hanging applications (you can also press command-alt-escape to bring up the Force Quit window).
B. The Library folders - you have two Library folders on your Mac. Mac Applications use library folders to store preference data, resources, and temporary files. The first folder, /Library, is system-wide (works across users) and contains a lot of system preferences and data for applications you have installed "for all users on this computer." The second one, /Users/yourusername/Library, contains user-specific settings. This is where you will find the vast majority of application settings and resource files. You'll remember that Trem's resources appear in /Users/yourusername/Library/Application Support/Tremulous.
C. Application preferences. You asked a question above about how to access Teamspeex's preferences, so I figured you might find this advice useful. Unlike in Windows where application preferences might be in the Tools > Options menu or something like that, on a Mac every app's preferences are under File > Preferences. This is where you need to head to change settings for any program. To change settings for the OS itself (system settings), use the program System Preferences (you might want to just open this up and look at every option to see what is going on on your computer).
5. Recommended software (go to macupdate.com and do a search to DL any of these):
A. Quicksilver - First thing I tell new Mac users is to download this program immediately. Its closest equivalent on a PC is Google Desktop, but Quicksilver totally blows it out of the water. QS offers instant access to a console-like interface that lets you search, open, and manipulate your files in real time. There are lots of plugins and options for system-wide hotkeying, and the power is basically endless. It may seem intimidating at first, but just hang in there and you will not regret it. There is lots of documentation for Quicksilver online, do a google search. QS literally saves me an hour every day.
B. Onyx - Gives you access to a whole bunch of hidden preferences, also maintenance and cleaning tools. Advice: don't muck around if you have absolutely no idea what a certain preference means.
C. iStat Menus - System monitoring information in your menubar. You can always have your CPU usage, network usage, RAM usage, fanspeed, temperature etc. at a quick glance. Basically essential for diagnosing any problem you might encounter, and for identifying when a program is eating too much RAM (although with 2 GB that rarely happens).
D. Adium (aka AdiumX) - the premier Mac chatting application. It's just the best, supports virtually all types of accounts and is highly customizeable.
E. smcFanControl - MBPs can get very hot, especially when gaming for hours when it is 90 degrees out already. smcFanControl allows you to control your fanspeed from the menu bar, so you can max it out before your system knows it is going to be doing a lot of work (I always set to 6000 RPM before opening Trem).
6. Useful websites:
www.macosxhints.com - the classic repository for all tips Mac. If you have any sort of problem or question it's likely the solution is here.
www.freemacware.com - they post a new free Mac application every day. Look through their archives and you will find many, many useful tools. BTW on a Mac, there is no such thing as adware.
www.macinstruct.com - a lot of articles and tutorials on how to do cool things with your Mac, ranging from beginner to advanced in difficulty level.
www.daringfireball.net - great commentary on all things Apple, will make you into an Apple cultist if you are not already.
www.tuaw.com - primary source of news for Mac users.
Well, that's all I have to say. I hope you find some of it useful and of course you can email or pm me any time if you have any Mac questions aand I will really be more than happy to answer them. I've been using Macs for 7 years now and consider myself very knowledgeable. Enjoy your MBP, man!!!