The long awaited SP1 for .NET 3.5 and Visual Studio 2008 are finally here! ISO is available here and EXE – here. Before installing you need to run Visual Studio 2008 Service Pack Preparation Tool in case you had SP1 beta or some hotfixes installed earlier.
And, of course, here is the .NET Framework 3.5 Service Pack 1 itself, either as a bootstrapper or as a full package. Note, that you do not need these if you are installing VS2008 SP1 – .NET 3.5 SP1 is already included with it.