You need to use an EBOOT.PBP form of the PS1 game. Their are tutorials in the tutorial section - look at the master tutorial list.
Once you have the eboot, stick it under..
When you load a psx game, hold down the R button to change the version of pops. But when you first run it, it asks you which to use and it will use that version until you change it.
thanks man! just one more question i downloaded the eboot for this ps1 game and put it in psp\game and when i go and try to load it it says corrupted data why is that?