Microsoft Announces Help for DVD-less Netbook Win7 Installers
Microsoft has released the Windows 7 USB/DVD Download Tool. This tool will allow you to take the ISO image for your Windows 7 install, and turn it into a bootable flash drive image.
Once that's done, the netbook's BIOS must also be modified to set the boot order so that the USB drive is first on the list. It's pretty simple to be honest.
Just remember that, according to Microsoft's site, this isn't a general purpose tool designed to turn any ISO into a bootable flash drive image. While we haven't tried it ourself, Microsoft is pretty clear that this can only be used with a Windows 7 ISO. Of course, we've heard that kind of "certainty" before.