[Haceldama]

what you need is a battery, a sony original can be put to be a pandora battery by software.
you'd need either someone who has a custom firmware running on his psp, or buy some tool from datel which allows you to set your battery into pandora mode. or buy a battery which only offers tool functionality, or a switchable one, if you know where to find one. there's also the possiblity to remove a pin from your battery which will put it into pandora mode permanently.
any of the above will do, then get some tool to prepare your memory stick.
then you can update to a custom firmware and play isos, no need for a pandora battery anymore, if you own an old fat psp.
if you own a slim psp, you might want to have a pandora battery handy, that will allow you to run some more homebrew apps, as not all are slim compatible.

in the end you need a custom firmware on your psp, there used to be ways to achieve that without a pandora battery in the past, but those depend on the exact firmware version and psp revision you own, and in general are less easy than a pandora install.
you can search for dark alex and pandora battery to find more info.

there are people who cfw your psp for you, free of charge or for a small price.
best you ask someone nearby who has a cfw'ed psp to help you out.