Ayre offers a stellar guide to configuring your Apple or Windows computer to use an Ayre DAC. These instructions can be used for most brands and models of D/A converters.
For Windows users, instructions are further broken down for XP, Vista/7, and 8.
For general and more in-depth computer audio information, please see the following links:
"The World's Greatest-Sounding Music Downloads"
The online computer audio guide
Forum and general information