With the Windows Azure platform, moving your application to the cloud is not an all-or-nothing story. The flexibility of the platform allows you to gradually move your application into the cloud (Software as a Service) or extend your application with new functionality (Software + Services).
In a first step, you may decide to move only your relational data into the cloud using Microsoft SQL Azure, and leave the rest of your application untouched. This approach allows you to take advantage of the cloud-computing platform with relatively little effort and impact on your existing on-premise or hosted applications. Start small, benefit big.
Not convinced about the advantages of Microsoft SQL Azure, check out this analyst report from Forrester Research, where they interviewed 26 companies using Microsoft SQL Azure to find out about their implementations: SQL Azure Raises The Bar On Cloud Databases.
Still not convinced and want to try it for yourself, know that you can try Microsoft SQL Azure for free. Visit here for more details.