Original PlayStation games come to iPhone with new Gamma emulator
Gamma, a free emulator of the original Sony PlayStation, was added to the iOS and iPad App Stores on May 11th.

Screenshots from the Gamma emulator on the App Store
Gamma is similar to developer Riley Testut's Delta emulator, especially in terms of the interface. Like Delta, it allows customizable on-screen controller skins, and includes support for Bluetooth controllers as well as wired keyboards.
It supports both Google Drive and Dropbox for backing up your own game disk images as well as automatically-saved progress. Users can choose their own preferred method or service to back up the games and save stages as well.
No BIOS files are needed for emulation.
In our initial trials with the app, there are some execution issues. But, we're confident fixes are coming. Long-time emulator developer ZodTTD has a storied history building emulators for iOS hardware, with him developing early -- and excellent -- Nintendo 64 and TurboGrafx emulators more than a decade ago.

The Gamma emulator in action
It will also pull any game artwork for players once the game is running. As per the rules regarding emulators from the App Store, Gamma is free of charge with no in-app purchases.
Read on AppleInsider
Comments
I'd love it if at some point the original entities that own the rights to these games would offer to sell you ROM files. I'd happily support those game-makers again.
If all of the other issues could be resolved, this final issue would be likely to stop things cold. It is clear the content is already available in the wild but there is going to be an obligation on the part of any distributor to prevent additional piracy. That means each group would either need to implement an existing DRM solution, which emulator apps would need to adopt, or some new approach would be needed. Honestly, the only way I see this happening would be for an intrepid emulator dev to approach content owners and form a partnership.