Linux User and Developer magazine has posted it’s 4/5 review for the Wolfson Audio card. The card allows high quality input and output of audio through the GPIO pins and uses the P5 header of rev 2 Pis. It appears to be a good bit of kit but the software lets it down and is still very young. Read the review here. You can buy one of these cards from various suppliers including The Pi Hut for around £30.