He's just talking about loading up a netbook with some sort of metasploit payload or in HD's case, probably a super awesome magical payload that no one knows about. More than likely he just adds it to a startup folder on the box so that it runs every time they boot the netbook up. From there, he just pivots throughout the new network.
Depending on how fortified your client is would depend on how stealthy you need to be. Usually a reverse connect payload over 80 or 443 will get you what you want. If there is a real need to hide the payload from AV, you might want to look at a new post from scriptjunkie. I helped him get a payload 100% undetectable:
http://www.scriptjunkie.us/2011/04/why-encoding-does-not-matter-and-how-metasploit-generates-exes/
Tutorials : Hacking Scenarios 
Hadnagy : [Article]-An Insider`s Look at the Social-Engineer.Org SE CtF at DEFCON
Editor-In-Chief : Free Webcast: Don't Pick the Lock, Steal the Key - PW Auditing with Metasploit
Links to cool sites. : Ninja-Sec Challenge You !
