Before installing any emulator, you need a PS3 ready to boot homebrew applications. This requires either or PS3HEN (Homebrew ENabler) . Each has specific compatibility requirements:
The journey of MAME to the PS3 spans several years, with multiple developers contributing. Here is a timeline of the key releases: ps3 mame emulator pkg verified
You can load ROMs directly from your USB drive, or transfer them to the internal HDD using a file manager like multiMAN. Before installing any emulator, you need a PS3