There is AppMakr for iPhone and App Inventor for Android for point and click app making needs and now iamjaydesai.com is working on a Simple App Maker for Windows Phone 7. It is not very feature rich at the moment but he plans to add more features to it.
At the moment It will accept RSS Feeds, Facebook and Twitter feeds via the web interface and you can choose a background and when you click “XAP It” ( XAP are the file format for Windows Phone 7 Apps, think of it like the new CAB ), the app will create a Silverlight app for you that you can deploy on the WP7 Emulator and you will have your first WP7 app running in a matter of minutes !!!!. You cannot customize the Logo and Name of the app at the moment ( keep in mind this is just a tech preview and not a finished Product ). He also talked about plans to include Flickr and perhaps Youtube integration to the app in the future.
Since this is still in development you will need to have a password to create your own app. You can request a temp password via Twitter @desaij
Click to try it out : http://iamjaydesai.com/wp7/makemyapp.php