Comment Summarisers (Score 2, Interesting) 38
I think one of the problems is that such a piece of software would be big business.
I think I found something in the Natural Language Processing Software Registry: http://registry.dfki.de/
Check under sections->written language->summarization
Another poster described systems that simply filter through relevant sentences. They're also sometimes known as abridgers. You might want to include that term in any keyword search you're doing