Roller Coaster Clubs

Roller Coaster Club of Great Britain - Coaster Fans from the UK

European Coaster Club - Coaster Fans from Europe

American Coaster Enthusiasts - Coaster Fans from the US

Sites I use all the time

Screamscape - The best source of coaster news on the net

Roller Coaster Data Base (RCDB) - The best source of coaster data on the net

Also worth a look

Save Dreamland Campaign

Boz Adventures

Coaster-Count

CoasterFanatics

Coaster Counter

The Coaster Critic

Theme Park Syndicate

Ultimate Coaster