One of the important features of OneNote 2010 is its ability to synchronise via Windows Live SkyDrive with copies running on other computers, the OneNote Web App, or OneNote Mobile on Windows Mobile smartphones (including Windows Phone 7).
What's been missing is an iPhone/iPad version. Microsoft has this week plugged that gap with the (initially) free OneNote app. It also runs on the iPod touch, but at this stage appears to be available only in the US App Store.
Features include creating lists with bullets or checkboxes, adding photos directly from the iPhone camera or from the album, and synchronisation via Windows Live.
There are some limitations. According to Microsoft officials, creation of new notebooks and the reorganisation of a notebook's contents must be done in OneNote 2010 or the Web App. And judging by early comments from users, OneNote hasn't been optimised for use on the iPad.
There's an initial fly in the ointment - see page two.
Some commenters have questioned why a Windows Live account is necessary to use the program, but synchronisation is a central feature of the app. If you want a standalone note taker, there are alternatives.
These two issues help account for the extreme polarisation of customer ratings at the App Store. At the time of writing, 78 people had rated OneNote, 38 giving it five stars and 26 giving it one star.
Questions remaining include when will Microsoft make the app available in the rest of the world (probably not until the login problem is fixed), how much will it cost after the introductory "free for a limited time" offer ends, and is an Android version under development (probably not, but you never know)?