What's port forwarding/port mapping?
Most routers these days can be configured automatically by Setup on Slingbox.com using a technology called Universal Plug and Play, or UPnP. However, some routers need manual configuration, and that's where http://portforward.com/english/applications/port_forwarding/SlingBox/default.htm comes in. It takes you by the hand and walks you through the process of configuring your router for port forwarding.
Take a look at the articles below for more information.
If Automatic Set Up Fails...
If you had trouble setting up your router with your Slingbox, please let us know!
Other Networking Articles...
This article explains port forwarding or port mapping in simple language.
Does your home network have more than one router? Here's a how-to for home networks with a little more complexity.