I am developing an ASP.NET MVC website, which I want to host on Azure Websites. While in development, I have been using an MDF file in my App_Data directory with a connectio
You'll have to use SQL Azure to use the Websites/Cloud Service features.
If you haven't already you'll probably want to have a look at web.config transformations with web deploy to ease the publishing experience.
http://msdn.microsoft.com/en-us/library/dd465318(v=vs.100).aspx
http://www.hanselman.com/blog/TinyHappyFeatures3PublishingImprovementsChainedConfigTransformsAndDeployingASPNETAppsFromTheCommandLine.aspx
You can import your data into the SQL Azure DB via the management tools or if you're using SQL Server 2012 you can import/export data via the portal.