Mac uses EFI but it emulates BIOS as well, that's how they used to achieve compatibility with Windows.
I think your best bet is finding out the specific model of your Mac and help.ubuntu.com should have full instructions. I wouldn't get an external DVD drive as I hear some Mac's can't boot from those either.
peakish's suggestion is great, if you just want to learn some stuff using a VM is much easier.
.
Yea well I didn't install Ubuntu using normal bootcamp so maybe theres the problem, I don't know. I borrowed an external DVD drive from work so I'm going to try it out. If it doesn't work I'll just run VM like you guys say.
My other option was to just keep booting up Ubuntu using the Live CD partition I made that lets me "Try Ubuntu", but I don't think that would save my work or whatever I do on it.