RabidWeezle's Tutorial for making game backups

What you need:
A PSP 1000/2000 series with custom firmware
A usb sync cable
A PC
(optional) A softdrink/beer of your choice

Alright you got like 50 umd's sitting around and you don't feel like hauling them everywhere, And you have a pretty big memory card (4-16 gigs). Here's what you need to do.

Install Custom Firmware. If you have a PSP 1-2000 series you can do this with a pandora battery kit if you need to. You can search for one on google with either "Pandora Battery" or "Psp tool battery". They sell em on ebay and other sites. You can also make your own but I'm not getting into that. This guide is assuming you are running Dark_alex's custom 5.00 m33-6 firmware.
Turn on your psp
Wait for the XMB to come up and press the select button. A menu will come up
Go down to USB Device and press left or right on the dpad till you select UMD Disc
Press Select again
Hook up the usb cable between your pc and psp. On the PSP, Go all the way to the left on the XMB and the 2nd entry from the top [USB Connection] and press X. This will start the usb connection to the computer.
On the computer it should pop up and say something like, "What do you to do with the device" or something of the sorts, click view the contents of the drive or something of the sorts. (I don't have my link cable with me so don't expect perfect quotes). A folder will pop up with 1 single file in it. It will have the .iso extension. Merely drag drop that file onto the desktop, or copy paste it into the directory of your choosing.
Now you can just go and take that iso and stick it in your memory card now under <driveletter>/iso BUT I don't think you want to unless you want to be out of memory card space in no time.See sony puts dummy files in their iso's and update stuff you don't care about that bloat the iso to insane sizes. so get UMDGEN (attached to this post at the bottom) and run it through there. Basically you want it to automatically remove the dummy files/update files and such. When it's done, save it to a CSO and Then stick it on your memory card. Much smaller.