I saw this title - Autodesk Releases Service Pack 1 for Revit Architecture - on TenLinks Daily yesterday and thought I would clarify what it meant. This is NOT a service pack for Revit...it is a service pack for the AutoCAD portion of Revit Suite (Architecture and Structure). There are 4 separate downloads for the AutoCAD 2009 Service Pack 1...AutoCAD LT, AutoCAD, AutoCAD Revit Architecture Suite and AutoCAD Revit Structure Suite.
Please make sure you download the correct service pack for the version of AutoCAD you are using. And remember, Revit uses Web Updates not Service Packs for the updating process.