Surveys and profiles of Internet users are a highly desired resource by businesses starting new web ventures, and researchers studying the Internet's effects on society. Numerous web sites offer detailed profiles of Internet users, but often for a large fee.
Broader statistics are more likely to offered for free, as part of press releases and news stories.
A great collection of shortcuts to the best Internet stats sites. The name of this site masks the fact that it is a well-organized collection of the latest statistics about the Internet economy. Includes a sub-category specifically for surveys that is also worth a look at.