Via David Sparks over on Macspark.com:
Several website, including The Verge, are reporting that Microsoft is about to announce Microsoft Office for iPad. While we've heard this before, this one feels more real than past promises and threats. I believe there has been a war raging on the inside at Microsoft between factions that wanted to keep Office on Microsoft Platforms only (to help drive sales of Microsoft platforms, like the Surface) and those others that see the iPad as a 100 million plus potential Office customers. I bet it was ugly.
I think Microsoft has realized they need to get their apps everywhere and let people use them on whatever platform they choose, including iOS. They've long supported the Mac platform with Office for the Mac so it's interesting that up until now they've drawn the line at "mobile versions".
Microsoft recently released OneNote for the Mac for free in the Mac App Store which compliments the previously released OneNote for iPad and OneNote for iPhone.
Getting people to lock in to your platform - Office365 subscriptions in Microsoft's case - is the hard part. Once you've got them, give them the ability to work with their data on your platform on whatever device they want to.
Eventually they'll choose a device based on whether it works with your platform but until you've earned that, people are going to choose a platform that works with their device.