Great VSTO Resources
PSS VSTO 2005 Client Troubleshooter
Download this brand new tool to make it simple to diagnose and remediate issues arising from missing or misconfigured prequisites on VSTO 2005 client machines. Gives a great report on the state of the machine and its components:
VSTO Application Manifest Editor Sample
Sample application (with full source code) that allows you to inspect and update the application manifest file embedded in VSTO documents.
Manifest Generation and Editing Tool
Not strictly a VSTO-related app (designed for ClickOnce manifests), but can be used with VSTO deployment manifests. Drag a VSTO deployment manifest into the MAGEUI window and inspect and update the manifest. Ships with the .NET Framework SDK. Details in MSDN.
White Papers and Documentation
Deploying Visual Studio 2005 Tools for Office Solutions Using Windows Installer (Part 1 of 2)
Deploying Visual Studio 2005 Tools for Office Solutions Using Windows Installer: Walkthroughs (Part 2 of 2)
VSTO Security MSDN documentation
VSTO Deployment MSDN documentation
Security and Deployment walkthroughs
Visual Studio 2005 Bootstrapper
VSTO Outlook add-in architecture