Performance under Mac OS X isn't as good as under Windows, so installing Windows via Bootcamp should be something to consider. But that's by no means a must.
As stated, remotes connect via Bluetooth. There isn't much that needs to be setup with a Mac, if I remember correctly, it's an easy process. And yes, the sensor bar works via IR, so any IR source should be good enough. A cheap method would be to buy some IR LEDs and create some simple circuit with a battery or two, which could then be easily taped to a monitor. Candles are nice and all, but hardly a permanent solution... (the wireless sensor bar is an easy option, but they tend to be overpriced).
The actual games themselves are generally in .iso format. There are homebrew tools to rip them using your Wii via SD card or via Wi-Fi. Alternatively getting them online is an option, but legally, uh... shady of course...
A lot of games run fine, but then again, a lot of games glitch at least partially. If you're looking to play
SS, there are still issues with Motion+ calibration, and the paint effects don't really work. Games like Super Mario Galaxy lose the atmospheric effects around planets. But games like
SSBB and
TP run charmingly well, as do many GameCube games. There can also be a lot of tweaking that needs to be done to get a game running at acceptable framerates, and often some of the graphical capabilities need to be given up to achieve this.
Best way to get familiar with it is to download it, skim through the manual, and try to get a wiimote connected and a game running.
(I'm only 9 days late, posting this...)
And Flex, how about some details? Do you meet the minimum requirements? Are your games in a proper format (like, umm... not PS3 games or something)? How far do you get before it starts mocking you?