When Apple released Boot Camp, they made it easy for anyone to dual-boot their Intel Mac with OS X and Windows. A recent discovery from the people that were able to get Windows booting on an Intel Mac before Apple came along with Boot Camp allows you to triple boot with Linux. Unlike the Boot Camp method of installation, some advanced tinkering around with chainloading Linux's lilo bootloader from the XP ntldr bootloader is required. It's definitely clear that Apple's Intel Macs are an extremely valuable commodity to the computer enthusiast, letting you run every OS under the sun.
Apple reserves the first primary partition for its bootloader. That leaves one for each operating system, but Linux needs two partitions -- one for the operating system itself, the other for the swap partition. You can get around this by using a swap file instead. This is a tried and true way of getting around this kind of problem. Unfortunately, swap files tend to run slower than do swap partitions, so if you're running multiple Linux applications on a Triple Boot Mac, you can expect to see a performance hit.
The OnMac wiki has the specifics of getting triple boot running. This is exactly what I've been waiting for. I don't think I can effectively run 3 operating systems on my 80GB hard drive, but having a platform that can run not only OS X and Windows but allow me to tinker in Linux (I'd opt for Gentoo or Ubuntu distro) from time to time is indispensable.