The ones I mentioned are the best.
Edaboard is full of people with lots of knowledge in all sorts of electronic components. Especially Analog electronics.
If you guys are tinkering with Arduino's, check out their official forum. That is the best resource for Arduino's.
You did not get a response to your queries from these forums?
If you want to know the theory, I will refer you some books. For practical applications, check the forums and blog posts.
A google search will turn up lots of answers.