Help with GRUB on USB Stick

I have a 4GB USB drive, and I want to know how to install BackTrack 3, Slax, and Ophcrack (not the module - bootable iso is what i want) on it all at the same time. So is there an easy to use Boot Manager (with image if possible) out there that I can put on the USB so when i boot from the USB, i can choose one of the OS's to load? Also, please do not include any burning of CD's/DVD's as I do not have a burner. Freeware too please. Thanks.

NOTE: I tried WinGrub but i could not figure out how to boot multiple OS on excpet when I paritioned it but with partiions, I had to force install the boot record thing and when booting from the usb caused errors. I do not understand the hd(0,0) thing. Whenever I boot the USB i get this:

Try hd(0,0) : No GRLDR
ERROR