Yes, of course there is. This is the best emulators site I've found -
PSP Emulation News PSP Gaming PSP Hardware PSP Homebrew PSP hacking PSP Updates Playstation Portable PSP movies PSP consoles PSP Shop Buy Preoder PSP Here
Go there and scroll down the page until you find the emulators section on the left side.
If the emu requires 1.50 CFW, you will need to install timemachine which you can get at
Dark-AleX - PSP Developer