Just read the announcement in Jason Langridge’s (Microsoft’s Mr. Mobile) blog about the release of…

Microsoft Office Mobile 6.1: Upgrade for Microsoft Office 2007 file formats

This upgrade lets you work with (read and write) Office 2007 generated Word, Excel, and PowerPoint files. The upgrade is only for Office Mobile on Windows Mobile 6 devices. So, if you have an earlier generation device, this upgrade is not for you. Note that this upgrade is relatively huge at 6MB. However, the system requirements section says this space can be on a storage card. So, presumably, you can install this on a flash card instead of using up system memory.

The download page also mentions that it is possible to buy Office Mobile 6.1 if your device does not already have it. But, the link provided there just leads to a general Office Mobile information page at this time. I don’t see any link or graphic indicating this purchase can be made today.