Ive been reading on the forums for a couple of days about this ,but all i seem to get is outdated info,So i was wondering if anyone has actualy seen how this works,or if everyone here use custom firmware?and if someone has seen how it works it would be greatley appreciated if you could tell me how to do it.... LEGALY.
I own a psp slim and its upgraded to 3.93 thanks i advance

I'm pretty sure you can only buy certain PSX titles from Sony; they don't let you convert your PSX game discs/ISOs. That's why most of us here use CFWs.

It's simple. There are only 2 steps;

1) Install the latest Custom Firmware
2) Convert your PSX ISO into a PSP formatted file

Installing custom firmwares is a separate question. As for how to convert your PSX games, look here.

Yes your tutorial was the first article i had read on this site and it would seem i realy DO need custom firmware ,But im terrified of downgrading, and is their another way to do it without the pandora battery(im sorry if im bothering you guys but im technilogicaly impared )

It's not a problem helping you out. You have a Slim PSP running 3.9x firmware, right? To downgrade that and install a CFW you definitely will need to use the Pandora Battery. Have you read through how to do that?

Basically you can get the files here but will need a PSP with CFW already installed in order to create the memory stick and battery needed.

Since you have a PSP Slim, Pandora's Battery and Dark_AleX's Despertar del Cementerio are your only options. As long as you can follow simple instructions, there is no need to be afraid of downgrading.

Okey dokey but ill have to get a pandoras battery off ebay or something though, i know ive seen several.Thanks alot Ill let you know if i have more trouble.

You should try

If the PSP is so similar to the PSX I wonder why no one has come up with a good PSP emulator.

The PSP is nothing like the PSX.

explain in electronic terms please... I know both are MIPS except one is 10 times faster, but are psx games on it emulated or is the hardware made for it too.

PSX games on the PSP are entirely software emulated. There is no dedicated hardware inside the PSP for playing the PSX games.

I actually had the idea that they were similar. So sad then