Dear felipemdc: Did you try to upload a single program to a Windows Phone 7 device and ran it?
No. To start with I don't have access to any Windows Phone 7. Where I work we have hundreds of Android phones, hundreds of Brew phones, a lot of Symbian, J2ME, Blackberry, iPhones, Windows Mobile 6. And many tablets. But zero WP 7 because it is completely incompatible with the tecnology that we use.
And anyway. Even if it worked, the resulting application would not be allowed into the Microsoft store.
From my experience everyone that was doing Windows Mobile 6 has migrated to Android. I'd say that Android is the real successor. You can also write Lazarus apps for Android, like it was possible for WM6.
WP 7 is only for .NET, not real programs.
And anyway, WP 7 is a massive fiasco. It has less than 1% marketshare which was gained at the cost of a huge debt and the near destruction of Nokia.