Know-How Exchange : Research/Metrics

It depends on what type of research you need. What is the purpose of the research, what are you trying to find out etc. If you live in the States, various government websites have tons of information for free.

Your question is pretty broad. There are thousands of sites that could have value for market researchers. Which ones will be most helpful for you depends on your industry focus, the kind of market research you're looking at (e.g., qualitative, quantitative, secondary, analytics, etc.), and whether you want something that's interactive or just report and white-paper downloads.

For example, the US Government's Statistical Abstract of the United States is useful if that's the kind of information you need, but useless if what you want is original survey research. Etc.

Actually, this forum is a very good starting place for sharing thoughts and asking questions. There are a number of prominent market research professionals who frequent this forum, and between them they probably know and have visited all the worthwhile sites already.

There's also a MarketingProfs seminar and how-to guide on market research that you might want to start with. They contain several suggested links for the various kinds of research you might want. The information on that seminar can be found at:

Do-It-Yourself Market Research

Good luck. Hope this gets you started on a useful path.