Does anyone know if it possible to install Windows 7, Vista, or Mac OS Snow Leopard via iSCSI?

This issue is more relevant nowadays for two reasons: installs sometimes don't fit on single layer DVD and netbooks don't have CD/DVD drives.

p.s. yes i've seen this mac from external hard disk method: Install Mac OS X from USB or Firewire Drive/Disk

and this mac from another partition method: Snow Leopard Install