Personally I got tired of waiting for the Playstation store to get ff7, ff8 and ff9 a well as Legends of Mana and Chrono Cross.
So I had my PSP hacked, and I used some software to convert my already owned PS1 games from from CD to psp.
Result? I could now play my games on my psp originally as intended, beautiful! FYI the psp already has a PS1 emulator in the firmware, the hack was basically so the psp would use my self extracted files from the CD's.
Graphics jsut don't matter when your playing a classic game on a decent sized hand held screen, ps1 in your hands I call it psp.
I like to think its legal as I already own the games and I bought the psp.
Personally I have used epsxe, the above mentioned software, when I imported Legends of Mana & Chrono Cross (cause they were never released in the UK hence not Pal). epexe has its problems when the game crashes or freezes or does not render, but also potenial with OpenGL and directX plugins to make the graphics quite superb.
But yeah, its not hard to buy the game second hand and extract the iso to play the game, but I only used it cause I could not play these great rpgs on my playstation so I imported it.