1) there is jpcsp a java based psp emulator for pc... no idea if code can be converted to work on ps3...see other emulations - nes, nds, etc.
2) the ps3 got interpreter + emulation selfs for psp(Minis) which are basically working on both psp+ps3 without having 2different compilations for each system (once compiled,signed,packed work on ps3+psp)
those minis are (mostly) packed as one bigfile eboot.pbp containing sfo,png and psp container (encrypted and signed?)
making retail psp games working would you require to somehow get the emulation working for them... either pack, encrypt, sign or making fully decrypted packages (psp eboot.bins decrypted too) and patch the ps3 emulation code.
not sure 110%.. but not possible so far -hw wise possible, sw wise not at all. and all videos about it are fake.
hope this explains smth.