This is probably a really simple question but I couldn't seem to find the answer very easily.

Is there a way to install Mac OS on an external drive so that I can connect to my PC (so that I can decide at boot up if I want to run Mac OS off of the external drive or boot up to windows)?

Thanks,

Install Mac OS X using whatever method you prefer to the external drive. Once installed re-direct your BIOS to boot from the external drive first. The BIOS will hit the Chameleon loader which will then offer to boot any installed operating systems that it see's. I use a similar method except all my drives are internal. I have mine set to load Mac OS X by default, but if I interrupt Chameleon it will then ask me which OS to boot.