Softgrid: Microsoft Release 4.1 Service Pack 1
Microsoft have released 4.1 SP1. SP1 improves support for sequencing SxS applications that have public assemblies, such as the 2007 Microsoft Office release.
Additionally there are a host of bug fixes.
Get it here.
Interestingly you can find out the difference between 4.1 SP1 and 4.2 here.