This is an intresting one we (Microsoft) is funding an open source project on SourceForge for an Office 2007 add-in to allow interoperability with .PDF, .XLS, and .ODF formats.
See the project site at http://sourceforge.net/projects/ODF-converter
OK so that is cool, I know I will use it but I have to ask… why? Microsoft (ok that is still we) also just announced a new open source site called CodePlex. What give why not use CodePlex? OK I know I am just a DE but come on mother ship!
Disclaimer The opinions expressed herein are my own personal opinions and do not represent my employer's view in anyway.