Is Microsoft Office 2008 compatible with Macs?

I've got a macbook, but MS 8 is required for a computer cl I'm taking. I found a download called "office 2008 for Mac", and I just want to make sure that it's the exact same thing before I go and spend $100+ on it. If I download this program, do I actually have Microsoft Office on my computer, or is it just a Mac-created imitation? Will it open as a normal Microsoft Word doent when I send it to my teacher's computer? I wish I was more tech-savvie... =\