The Google spam team have updated their spam reporting page to make it easier to report websites that are flouting the Google webmaster guidelines.
Matt Cutts of the Google spam team says it is the biggest refresh of Google spam report form in 10 years.
You have to sign in to your Google account to see it in Webmasters tools at https://www.google.com/webmasters/tools/spamreport
“”Webspam” refers to pages that try to trick Google into ranking them highly. “