Allowing readers to submit articles from other sites

I’m trying to find a plugin or method that will allow a user to submit a url, title, image and first paragraph for display on my WordPress blog, much like the way Digg operates (or pligg.com). Does such a plugin exist? Any suggestions on a way to hack it?

It would be nice if the user (registered and logged in) could simply enter a url, and then the plugin would ping the address and extract the relevant info for the user to edit and approve.

Ideas?