Ebay ElasWin workshop manuals are good about £12 Make sure you get the right one.
Basically its the manual that is installed on the Audi main dealers computers. It comes on two DVDs and covers every Audi, Volkswagen car from 1970 to 2004.
Not strictly kosher but very good, oh and my copy is strictly for backup purposes only, in fact I am just looking after it for a mate.
Edited to add its now just £5.99 and covers cars up to 2006.