Hi, I'm pretty much a newbie when it comes to Linux, and dual booting. I was wondering how do I dual boot openSUSE on a Macbook? Using Paralles or VMWare Fusion isn't an option for me because I only have 512 MB of RAM. Links to how-to guides are appreciated also :) Thanks!

The OpenSUSE site has an entire section dedicated to it:

http://en.opensuse.org/OpenSUSE_on_a_Mac

Hopefully that should start you off.