Retrieving corporate event information for listed companies

I would appreciate thoughts on a question pertaining to corporate event information:

What would be the "best" source for automating retrieval of eg dividends, ex-dividend dates, earning dates going forward etc.?

Would it be finance.yahoo.com? Can it "easily" be retrieved from Edgar parsing XML files?

I am well aware the terms "best" and "easily" are in the eye of the beholder, thus different opinions are welcome.