Prewar Car the site for old cars and parts.
Vintage Knowledge, hints and tips section is worth a look.
Restoration Supply Company good general car hardware (US)
Paul Beck Vintage Supplies parts for proper cars
Classic fasteners good Aussie site will send small quantities.
Classic Dynamo & Regulator Conversions also LED lamps
Vintagent a great vintage motorcycle site.
Barnstormers a rather eccentric Kiwi motorcycle site.
Car and Classic UK great car classifieds.
Narrywoolan a site about all sorts of things including the Lancia Aprilia.
Australian Lancia Register The Australian Lancia Club