I wrote previously about fixes that are available for three issues that can occur when you install SP1 for .NET Framework 3.5. In addition to those three CLR issues, there were some other problems caused by the service pack which is why we also released the rather cutely named "Family Update" for .NET Framework 3.5 just before Christmas.
Choosing what to download is a bit complicated because not only do you need to select the correct package for the operating system family you are using (Windows XP/Windows Server 2003 or Windows Vista/Windows Server 2008) but you also have to choose the right architecture (x86/x64/IA64). On top of that, once you have got to the right download page there are in fact three things you have to download and install - the updated bits for the core 2.0 framework, the 3.0 bits of the framework and also for the 3.5 bits of the framework.
Anyway, to streamline this we have now released both SP1 and the post-SP1 "Family Update" as a combined high priority update to Microsoft Update. So all you need to do now is go there and let it scan your system to tell you what you need and you should see something like this:
In fact if you can't be bothered doing that and you have automatic updates enabled, just wait and it should come to you!
The same size of download is offered irrespective of whether you have SP1 already or not. In other words it appears to be a single, cumulative, slipstreamed update with both SP1 and the family update. I'll see if I can find out more about that. I'm also wondering if it is possible to download this single cumulative update independently of using Microsoft Update.