Microsoft open the Windows Mobile & XBOX 360 app hub for submitting new applications just after launching the Windows Mobile 7 phones. If you are already registered as a developer then you can follow these 5 steps to upload apps to the Windows app hub.
Submitting your application consists of the following 5 steps:
Step 1: Upload Your Application
1. Enter basic app information and upload the .XAP
2. Add notes or instructions for the teams that test and certify the application.
Step 2: Provide the Application Description
provide details about your application that will appear in the Windows Phone Marketplace.
Step 3: Upload the Artwork
In this step, you will upload the artwork associated with your application.
Step 4: Set the Application Pricing
price your application and determine the markets in which it will be sold.
Step 5: Submit Your Application
This step allows you to review the details of your application before submitting your application to Microsoft for certification.
Enjoy developing application for WM7 and Xbox 360 and you can find lots of how to develop WM7 and XBox 360 apps here.