Downloadable through the Web Platform Installer this update adds some very nice features.
Profile applications running in Windows Azure
With profiling support in the Windows Azure Tools you can easily detect performance bottlenecks in your application while it is running in Windows Azure.
Creating MVC3 web roles
The new template includes the new universal ASP.Net providers that support SQL Azure and it will also make sure that MVC assemblies are deployed with your application when you publish to Windows Azure.
The Windows Azure tools now support multiple service configurations in the same Windows Azure Project. This is especially useful for managing different Windows Azure Storage connection strings for local debugging and running in the cloud.
The following explains the relationship:
Read more about the new features here.