bitbanger wrote: However, many computers lack the bios support for a boot from a usb device.
You have these options:
- use a boot floppy or bootable CD-ROM with a minimum kernel that will boot the rest off the device you choose (e.g. USB)
- upgrade your BIOS
- buy a newer computer whose BIOS can boot off USB devices
circumvent or defeat your PC's BIOS. If your PC can't boot off USB then there is almost nothing GRUB can do about this.
bitbanger wrote: Is there support in grub for usb?
You seem to have a misunderstanding about what GRUB does or what it doesn't. Besides, you should ask this stuff e.g. here maybe?