Before you rush to download SQL 2008 you may want to read the following KB article which warns that Visual Studio 2008 SP1 ‘may be required’ for SQL Server 2008 installations KB956139 (found here)

”Because certain SQL Server 2008 features install components that are also part of the release version of Visual Studio 2008 SP1, SQL Server 2008 requires Visual Studio 2008 with SP1. If Visual Studio 2008 without a service pack is installed instead, it may not work correctly after you install SQL Server 2008.“

Currently, Visual Studio 2008 Service Pack 1 (SP1) is in beta at the current time.

I do not know the expected delivery of SP1 but should be soon (hang tight).