Eric Wilfrid

Microsoft's Mac Business Unit, which makes Microsoft Office and other programs Apple computers, today scheduled a news conference call for Thursday, Aug. 13, without any hint of what it will be announcing -- saying only that it has "some exciting news to share." It's an unusual move for a division of the company that isn't known for big surprises.

We don't yet have any further insight, but if Microsoft were to come out with a version of Office for the iPhone, the Mac unit would be the natural division to produce it, given its experience writing software for Apple platforms. The conference call will feature Eric Wilfrid, the Mac BU general manager. When we quizzed him about the possibility of an Office app for iPhone earlier this year, he didn't rule it out.

"It's something we're looking at, clearly," Wilfrid said at the time. "Our mission is delivering Microsoft productivity to Mac customers. There are a lot of Mac customers who have iPhones, so we'll think about it through that lens. What is it that we might be able to do on the iPhone that would help Mac customers be productive, and contribute to the business that we've built and to the connections to Microsoft software and services. But we still don't have any iPhone news to share at this point."

Of course, it's possible that they still won't have any iPhone news to share next week, and the announcement could be about something else entirely. But Stephen Elop, president of Microsoft's Business Division, also has hinted at the possibility of an Office iPhone app.

Microsoft already offers mobile versions of Office apps for Windows Mobile, but an expansion to the iPhone would put the company in a delicate position, given the fact that it's planning to launch a rival to the iPhone App Store on Windows Mobile later this year.