There are MANY sites devoted to this, what may be considered a 'cult' or 'underground' game. As I have tried to keep this site simple, I will do the same for links. Below are what I feel are the most important links for VGA Planets. This is not to say the others are not good, but I find these to be essential.

Tim Wisseman's site for ordering the game, all important links, add-ons, etc. Don't Link home without it.
Rated as the BEST and most RELIABLE hosting site in the universe. Completely automated with TONS of games running daily.
An incredible resource saturated with information, add-ons, guides... you could spend MUCH time here.

Hats off to Donovan for a much better tutorial and resource than Echo Cluster... just not as pretty to look at :-)