I have a dream of my next desktop being a GREEN-friendly Multiboot machine with Snow, 7, and Linux.

However, I'm brand new! Can we get a FAQ for this topic? Links to guides / etc / wikis?

My questions are this:

1) I'm used to using Parallels in OS 10.4.11... if I triple boot, I'm assuming I have to make multiple partitions of the hard drive(s)...
Will I be able to use parallels to access files that are sitting in the other partitions?

2) What does triple boot exactly mean:
-are they running at the same time?
-or just ability to boot 1 of 3 operating systems.

Thanks for answering and humoring me with my noob questions.