RMPrepUSB is the application you need if you want to create bootable USB drives. they are useful now that most netbooks doesn't include DVD drives.
RMPrepUSB is a front end graphical user interface for the Windows command line program RMPartUSB.
RMPartUSB is a command line Windows program that can access USB storage devices, e.g. flash memory (UFDs) or USB hard disks or USB card readers, and partition and format them to make them bootable.
Supported Operating Systems that will run RMPrepUSB/RMPartUSB include: Windows XP, Vista, Server 2003, Server 2008, Windows 7. 32-bit and 64-bit versions are fully supported. WinPE v2 and v3 is also supported but the Copy OS Files option may not work and you will need to type in the folder path instead.
Bootable Operating systems: You can make a USB pen that will boot to MS-DOS, FreeDOS, WinPE v1, v2 or v3, BartPE, XP, Vista, Win 7, linux (via grub4dos or syslinux boot loaders).