Actually there are a few other methods that can be added here as well. Three I came across on how to use a usb flash or pen drive for installation of 7 can be looked over at the links here.
digg has the other one at http://digg.com/microsoft/How_to_Cre...lation_USB_Key
A third with an interesting look for the usb flash drive was found at http://www.feloos.com/?p=2841
PC World has one for installing 7 from an external hard drive. http://www.pcworld.com/article/16515...ml?tk=rss_main
As for activating 7 you simply use the same method as seen for XP or Vista. The fast click on the system icon in the Control Panel will display whether you are activated or not with the link seen with "Windows will automatically be activated in 3 days". That's seen in the "View basic information about your computer" screen.