The project uses a Texas PCM2707 chip for USB Audio in conjunction with a Texas TAS5727 2x20W D-amp accepting I2S audio @ 48kHz coming from the USB host, i.e. PC running VLC or what player have you. The role of the mini is to orchestrate it all.
Attached is an image depicting the setup using a FTDI cable for programming the mini (which could be omitted for clarity at this point). There's also a separate 20V line (coming in from the upper left) to power the TAS5727 D-amp. Then there's the USB-cable from the PC supplying 5V to the mini and a 3.3V regulator for the Texas chips.
The TAS5727 D-amp is controlled by the Netduino mini by means of I2C and the PCM2707 is controlled over SPI. More over this later, should anyone be interested.
Attached is the code for all of this, it includes code for doing USB-HID operations which will control VLC playback on the host PC after an IR-remote has been added. As a followup, I will include an IR-remote in order to control the host PC, i.e. play/pause/skip, etc.
Btw, the Texas PCM2707 (TQFP32) has been soldered onto an adapter by no other than yours truly and the D-amp thingy could really blow your ears out
EDIT: Here's a video: