I have written a blog post on beyondrelational site about a SQL Azure DMV – sys.dm_db_partition_stats that can be used to extract information about database size and size of each individual database object. To read the article please go to: http://beyondrelational.com/blogs/parasdoshi/archive/2011/05/30/sys-dm-db-partition-stats-a-sql-azure-dynamic-management-view-dmv-to-calculate-database-size.aspx