msdn.microsoft.com is the official site for any Microsoft product related questions.

google.com is also a useful resource, but one needs to be careful since the results can come from "anyone". There is alot of incorrect material on the internet, and much of the .Net postings contain incorrect or sub-optimal information.

I usually recommmend starting with msdn then google if necessary. If you find something that looks good on google, you will have specific keywords that you can use to confirm the information back on msdn.