Looks like I will be building an app for WP7 soon, perhaps even before I start on Android. This looks like such a modern developer friendly platform. I think we will see waaaay more internal business apps being built for WP7 than iPhone. Not many business apps were written for Windows in C/C++. I think Objective C is also too low-level for business apps.

http://www.msdnevents.com/wp7devlaunch/