Europe

Autobahnen - Exit lists for all the German Autobahnen.
www.autobahn-online.de/auswahl_e.html

Autosnelwegen.net - Exits and route numbering in Belgium, Netherlands and Luxembourg (the Benelux region). In Dutch and English.
www.autosnelwegen.net/intro.html

Autostrada del Sole - Italy's A1 and A2 in 1965.
mryamamoto.50megs.com/Autostrada_del_sole.html

5 Minutes Away - Directory of services and facilities within five minutes of each UK motorway junction, including those within service areas. Entries include junction diagrams.
www.5minutesaway.co.uk

Motorway Database - Database of the junctions on every numbered motorway in Britain. Includes junction diagrams.
www.cbrd.co.uk/motorway/