Noticed that there are a bunch of new tandem enthusiasts joining this forum. Welcome!
A good tandem club and source for information is the the Tandem Club of America (TCA), a club that has existed now for 30+ years, is national and international in scope and has no meetings to attend!
They do publish a magazine called DoubleTalk, six times a year that is loaded with all sort of tandem related articles and information.
Check out their webside www.tandemclub.org for details.
Membership is a mere $15 a year for US and $20 for folks up in Canada.
The latest issue, Jan. - Feb. 2007 has some great articles, including a tour in France with folks on a three-seater, "A Season of Three Stokers" article, two different views/reviews of the Midwest Tandem Rally sponsored by the PIGS (Paired Iowans Going Somewhere) in 2006, an off-roading tandem adventure weekend, a great get-TWO-gether of tandemistas in New Jersey, an Adirondacks riding report plus a rally in Kentucky!
Also a listing of tandem rallies/events across the US, a 'for sale' page and even occasional reviews on new tandems and tech tips/problems.
We have enjoyed being TCA members since the club's inception, way back in 1975.
So, if you're failry new to the tandem scene, the TCA is an excellent source!
Pedal on TWOgether!
Rudy and Kay/zonatandem