Ran into this today looking at Vista MUI stuff. . . Looks like I need to get a new version of the MUI's for SP1 . . which kind-of stinks. . . I understand, but it still stinks..
Windows Vista Step-by-Step Guides for IT Professionals
Here's a list of the guides you will find there.
And if you're looking to download some SP1 MUI Packs, thank my friend Christophe for this link.