If you are new to VSTO the hands-on labs (HOL) are a great way to kick the tires and try out the new features. These are labs that were featured at TechEd 2007 this year in Orlando so if you were waiting to go to PDC and missed it here they are for you to try.
MSDN Virtual Lab: Building Custom Office Applications Using Microsoft Visual Studio Tools for Office Part 1 - Data Binding with Word Content Controls
Part 4 is an especially good one to do as a HOL because VSTO Workflow projects require that you run Visual Studio 2008 on a Office SharePoint Server (MOSS). This takes a long time to setup and requires some good hardware to make it tolerable.