Does the Micro2440 have an audio output like the Mini2440? I think there should be a page on this site, with a table where both boards are compared.
Audio Out on Micro2440?
You have the I²S bus (http://en.wikipedia.org/wiki/I²S) from the s3c2440 to one of the headers.
The SDK for the micro2440 stamp contains the Audio in- and output jack + AD/DA converter. You can find this in the SDK shematics (http://www.friendlyarm.net/micro2440/micro2440-sdk_schematic.pdf) on page 4.