The VSTO Folks just released a new sample on Deploying a VSTO 3.0 solution for the Office 2007 using Windows Installers.

The code samples are written in Visual Basic and C#. The folowing list of projects and samples describes how you can integrate these into your solution to deploy with a Windows Installer file.
Projects - you can add these custom actions to your setup project.
1. Component Check
2. ClickOnceCustomActions - install into the ClickOnce cache
3. DocumentManifestCustomActions - update the document custom properties to point to the assembly
4. InclusionListCustomActions - add an entry to pre-trust your solution

Samples
1. Basic installer - Hello World add-in
2. Additional components - #1 + helper library
3. Inclusion list
4. Change Manifest
5. ClickOnce cache

http://code.msdn.microsoft.com/VSTO3MSI