Here are the slides from Krugman's talk: How will it end?
Note: This was before Bernanke talked about "credit easing" as opposed to "quantitative easing" again. Bernanke's approach appears to run counter to Krugman's argument:
"The only way to make monetary policy effective once you’re in such a trap, at least in this framework, is to credibly commit to raising future as well as current money supplies."