Klipsch 5.1 Promedia setup

[Molinjir]

I've posted several times here before, asking about speakers, but I finally decided the the Klipsch was probably my best bet.

Now, my question is, what do I need to run it properly with my computer. Please excuse my lack of knowledge on the subject of audio and soundcards, etc. in general. I noticed that the Klipsch has '6 analog discrete channels (3 stereo miniplugs), Auxiliary stereo miniplug music input'. I know little about this, but don't I want digital input?

I have a mac powerbook, and will be upgrading to one of the new Intel Core Duo iMacs within 2 months, what will I need to use these properly?

Thanks in advance,

~Molinjir