Here are some usefull sites:

Vehicle wireing products - for all your vehicle wiring needs

Ross-tech - Makers of VDCS

Crazy Quiffs Mk1 Golf emporium - All things mk1 golf

GPC - OEM parts for old VW's

VwAudi Forum - Great forum

Club Gti - Great site full of gems

Piston - Another great site, good clasifieds section

Newton commercial - Excelent company that re-makes interior parts for many clasic cars