Using USB Zero DAC with iMac

G'day Guys, hopefully I have a real easy question. I have never had anything to do with computers in the audio chain however have recently taken up the piano. Software is available to simulate the sounds of quite expensive pianos and the output is then fed to an external DAC and headphones/amp etc. Furthermore I thought I'd finally look at the music server side of things.

I'm interested in the Zero DAC like this 09 NEW VERSION ZERO 24/192KHZ DAC HEAD AMP @USB @OPA627 - eBay, Other, Laptop Accessories, Computers. (end time 10-Oct-10 19:32:57 AEDST)

I like this DAC as it's cheap, uses a good chipset, and seems to provide plenty of scope for further hacking. While very comfortable about the audio side of things, I know NOTHING about the computer end. This will go with an iMac computer, is it as simple as plugging this USB DAC into the Mac and it being recognised and streaming USB audio to it, or is there more to it? Unfortunately I haven't been able to find any examples of people using these Zero DACs with Macs, so don't quite know what is involved.