A few days ago Nokia announced that it would start using Windows Phone 7 as the main mobile operating system on all its future smartphones. I think this is probably a good deal for Microsoft. I do not see how this is good for Nokia though. This deal basically reduces Nokia to just a hardware manufacturer.
The worst part is that Nokia becomes completely dependent on Windows Phone 7 which as a platform is way behind Android. Nokia should have chosen Android, kept their investment in MeeGo, and provided Android and MeeGo migration tools to Symbian developers.