Unlike other Service Packs from Microsoft, the SP1 of.Net Framework 3.5 and Visual Studio 2008 not only contains bug fixes and improvements, it also contains new technologies such as ADO.Net Entity Framework v1, ADO.Net Data Services v1, ASP.Net Dynamic Data and the framework and tools support for working with SQL Server 2008 that was RTM'ed last week.
Here are some useful download links:
While downloading and installing the SP1 of.Net Framework 3.5 and Visual Studio 2008 you can take your time to read the posts I've written during the beta time frame:
Overview of the Service Pack 1
ADO.Net Entity Framework
ADO.Net Data Services
ADO.Net Sync Services
SQL Server 2008 and Data Access Technologies
Note: If you were waiting for SQL Server 2008 and couldn't install it, now you can.