As high lighted on a number of blogs as well as AUGI; new builds of Revit Architecture 2009 and Structure 2009 are available for download from the following locations. Note that this service pack is different as it now works like the Autocad service pack functionality.
Revit Architecture 2009
Revit Structure 2009
Revit MEP 2009
Edit. Just updated my version of Revit Architecture 2009 using the new service pack tool. As highlighted in the readme.pdf, it is crucial that you have access to the Revit Architecture.msi, else things will go wrong!
If you have updated Revit Architecture using the previous download from the web and you left it in its original download folder located C:\Program Files\Revit Architecture 2009\Download, you should be fine. Although you may still have to browse to the msi manually, I certainly had to; the msi can be found in the following folder.
C:\Program Files\Revit Architecture 2009\Download\RevitSetup\RevitBuilding
Overall, this is a very positive move forward, especially for those that have multi-deployments of Revit.