Link up to those who've spent much more time than we have putting together websites.
They went to all that effort -- check 'um out.
The Diplomatic Pouch is the primary place for all things diplomacy.
Any resource you could possibly imagine is avaliable to you on this site. If you've never been, be sure to check it out!
The Windy City Weasles are located in Chicago, and are highly active in the Diplomacy community. They host an annual tournament, the Weasle Moot, which you can find out all about on their site.
The Bay Area Diplomacy group is bringing together players from all over Northern California.
The Vancouver Diplomacy website is a good source for what is going on with our friends in Canada.