Riders Rally- My favorite of all forums for Goldwing riders. If you know how to use their search engine you can find a bunch of outstanding tips here.
GL1800Riders - A lot of Goldwing folks on this site. Occasionally they get around to talking about Goldwings. This is more of a social gathering than a technical resource.
ST-Owners.com - About the friendliest and most helpful ST1300 and ST1100 owners you'll ever find. This site is extremely well organized. You could spend a day just digging through the Knowledge Base.
St1300.US - A good secondary resource for all things ST1300 related. The Classified Ads area is always busy.
Spirit 750 - These guys and gals will always hold a special place in my world. The are some of the most helpful and friendly folks you can ever come across. Even if you don't have a 750 SS, you'll want to hang with folks like these. For them its the ride, not the bike.
The Spirit World - Another 750 Spirit forum, these guys crack me up! They wear their rudeness on their chest like a badge of honor, but they are a blast to get to know and would give you the shirt off their backs if it kept you riding. Warning: this site is Rated R for language and vulgarity.... its like hanging out at a biker bar in the Mojave Desert. You must register to even view this forum.