Triple boot Mac, Windows, and Linux, without using Boot Camp

If you’re looking for a solution to triple boot Mac OS X with Linux and Windows without using Boot Camp, you can do this using a third party boot menu called rEFIt, which shows a menu like the above screenshot on each system boot.
If you’re already familiar with multi-OS setups, partitioning, and the like, you probably won’t need a walkthrough since the setup is pretty straightforward to those who have experience in dual/triple boot environments.
If you’re new to the topic though and would like some more assistance in setting up a triple boot OS environment, LifeHacker has a write-up although it’s sort of just stating the obvious: install rEFIt, partition drives, install OS’s, and of course the rEFIt documentation is another great resource.

can rEFIt boot a system from an external drive as well?
yeah, i would like to know that as well…