I'm looking for either an URL with a feedback form or an email address.
Search for something, for example Webapps, and then click on the
Give us feedback at the bottom of the resulting page. The rest is up to you ;)
Unfortunately Google no longer shows the "Give us feedback" link at the bottom of search results, so you will have to bookmark the link provided by Mr. Palavuzlar. There is also an unofficial bug tracker here: