News feed for *just* earnings announcements?

I'm trying to find a source for company earnings announcements that I can rely on programmatically to see if a given stock has announced earnings that day. The closest ones I've found so far are by Yahoo Finance and MSN Money:

Earnings News Archive - Yahoo! Finance
Latest Earnings Reports Business News and Commentary - MSN Money

But both of these have the same problems:

1) They don't even include all of the sources that are available on their websites (e.g. GlobeNewswire, Business Wire and Marketwire). And when searching through those sources individually, there is no single text search pattern to reliably match only earnings-related news.

2) They include *non-earnings* news such as dividend announcements and scheduling of conference calls.

Can anyone suggest any good sources for this information?