We have blogged in the past about SQL Azure to SQL Azure
synchronization using Data Sync Service for SQL Azure (Introduction
to Data Sync Service for SQL Azure).
However what if Data Sync Service doesn’t do exactly what you want? It stands to reason that the Service will be
adding more features as it matures, however if you need a custom
synchronization you can easily program your own using the
Sync Framework V2.1 Software Development Kit and a Windows Azure worker
role. This newly
published wiki article shows how to synchronize between two SQL Azure
databases using the Sync Framework SDK and a Windows Azure worker role.
Read the Wiki