Useful links:

http://www.alfisti.co.uk
A large site full of information on things Italian and Alfa Romeo, with some Minari information.

http://www.alfabb.com/bb/forums/archive/index.php/f-43.html
Boxer engined alfa forums - some good stuff here

http://www.alfaboxertuning.fws1.com/
Alfa boxer tuning - comprehensive details for tuning your engine

http://www.aroc-uk.com
Alfa Romeo Owners Club - has active AlfaSud and Alfa 33 Registers, and forums for members