We have a guide on how to do that here, a bit of hand-holding to prevent this (ounce of prevention...) never hurt :)
I gave it a shot, and it just won't load to anything.
Do you want me to move the .dol file or just copy it to the root? i've tried both ways and it won't load. I set the options as installed file and autoboot and nothing happens. I just can't get it to load straight to the usbloader gx. What I can tell you is, I have the 0.7 Priiloader.
your guide mentions .03b, where can I download that? should I be?
Download THIS and put it on the root of your sd card. While in priiloader select to install it, then make sure you are set to boot to installed file.
BOOM, worked like a charm THANK YOU :)