Login to https://windows.azure.com
Click on Reporting tab on lower left hand corner
Click on “Provision” button
Select the Windows Azure Subscription account and then click “Next”
Enter the Invitation Code and specify the password and click “Finish”
Now you have successfully configured your SQL Azure Reporting Service account
You can publish your reports from BIDS to the Web Service URL using the Username provided and Password you have setup.
Good Luck !!!