What prominen tweb sites are concerned with reporting or publicizing wrongful business practices, fraud, etc.?

Answer 1

The Better Business Bureau is definately a good way to go. They're usually very involved locally, which is a big plus if you're talking about a smaller business.

www.bbb.org

Also, depending on the type of infractions, the Securites and Exchange Commission. If laws have been violated, the SEC is always happy to investigate.

http://www.sec.gov/

Answer 2

the better business bureau and the courts. police departments.
govt websites that license people and business find out if they have been revoked lost the license etc.