A good video tutorial for anyone starting out with GNS3. His tutorials are what got me started on Dynamips in linux :). Always a good place to start…

In this tutorial, you will learn how to build a Cisco switching lab … even though GNS3 cannot emulate a Cisco switch. I will show you how to use an NM-16ESW network module in a 3640 router to emulate a switching environment.

This tutorial is actually part one in a two part series. Part 2 will show you how to configure a “router on a stick”. A router on a stick is basically when a router is configured to route between two vlans with a single physical connection to the switch.