The American Journalism Review has this article about Wikipedia being used by people in the newspaper industry.
My response is that Wikipedia should never be used as a source in a an article for an news medium.
That being said, I do believe that Wikipedia is a useful tool to find some basic information about subjects you may not be too familiar with.
I even have linked to Wikipedia topics from this blog and my other blog. Do I trust everything on Wikipedia? No. Should it be read with skepticism? Yes. Is it OK as a quick read on a topic? Yes. Should it be the final read on a topic? No.
The most useful part of Wikipedia is any links at the bottom of an article. These are usually source notes and can lead you back to an original, more credible (and possibly even one that could be used as a source in an article) sources.