http://www.epsxe.com/
Oh, and if you want information about the best configuration for it...
http://forums.eyesonff.com/showthread.php?t=85175
is a thread posted not to long ago about good ePSXe configurations for FF7.

You might have trouble finding an iso of FF7 and PS bios (a PS bios is a file that ePSXe isn't legally allowed to use in their emulator so you have to find elsewhere). If you fileshare you should be able to find them though.