IMdb  Guy's page on the Internet Movie database. Well-informed and regularly updated. 

IMdb  'Allo 'Allo! page

Wiki  Guy's Wikipedia page

Wiki  'Allo 'Allo! Wikipedia page

Memory Alpha  Startrek page

Cafe Rene  American Mark Thompson's site is no longer active, but still an exhaustive chronicle of everything 'Allo 'Allo!

Picture Gallery  Lots of good quality screen grabs from 'Allo 'Allo!

Phill  'Best British Comedy' 'Allo 'Allo! page

AMTV Radio  Adam Martin

Kim Hartman   The lovely Kim's website - (Private Helga Geerhart)

Richard Gibson   The lovely Richard's website - (Herr Flick)

HelgaGruberFlick   Official website the 3 favourite characters

HelgaGruberFlick on ebay  ebay site for photos & merchandise