I use Wikipedia as a starting point, in that it gives me ideas of what to look for from more reputable sources. (It also acts as a filter, because if I see the same thing on another site, I know to disregard the whole site.) Depending on what I'm researching, I'll look for journals or other "expert" sites, or I'll look for blogs or other ways of contacting people individually.
I should add, I'm not a good "face-to-face" researcher, so while it's very good to be able to meet with or call people for info, I much prefer finding a contact email addie. That can often result in more detailed info and easier exchange of questions/answers, as people don't have to rush or set up an appointment, etc, and if you think of something later on, just shoot them another email to be answered at their discretion.
"It seems rather like wanting to be ... a writer, rather than wanting to write. It should be a by-product, not a thing in itself. Otherwise, it's just an ego trip." - Roger Zelazny