Beth Massi has been busy creating a number of great posts describing how to build add-ins to Excel, Outlook, Word, etc to work with data from an ADO.NET Data Service. The articles can be found here:
ADO.NET Data Services - Building an Excel Client
OBA Part 1 - Exposing Line-of-Business Data
OBA Part 2 - Building an Outlook Client against LOB Data
OBA Part 3 - Storing and Reading Data in Word Documents
Also, Beth graciously offered to convert the code samples from the current "Using ADO.NET Data Services" whitepaper to VB as they are currently only available in C#. We're working on getting the VB snippets integrated into the document, but for now they are also available here.
ADO.NET Data Services, Program Manager