So far I've not found details after an admittedly quick search. The following headline is on top of the NYTimes.com hompage ...
Breaking News 10:03 AM ET:
Kenneth L. Lay, Ex-Chairman of Enron, Dies, According to Reports
I'm swamped at work, so anyone with more info please add to this in comments.
I'd add a first attempt at analysis, but need more information - will update this diary as it comes in IF this report is true.