I have been using the Google Websearch API for over 1 year now. The service was deprecated in Nov 2010 but continues to provide results to date. More recently, google has st
UPDATE: @ggez44 points to some official Google documentation of the solution described below here: http://support.google.com/customsearch/bin/answer.py?hl=en&answer=1210656
You can use the Google Custom Search Engine to search the entire web.
In brief:
Full details here:
Once that's implemented, you can enable billing in the Google API Console at a CPM of $5, to a total of 10,000 queries.