E2MAME for Symbian has been around for years. It works with mame .v32 (or thereabouts) roms.
I had it on my 300mhz Nokia N95 8GB for a while. Games from the early 80's work well.
Mid 80's games were too slow to play.
I also have a Zeemote JS1 bluetooth controller that works with the phone:

The thumbstick is pretty good, but ultimately the controller suffers from the same problem as a phone.
Everything is too close together & too small to play comfortably.
I wish they'd used a gamepad layout instead.
I've thought about hacking it and trying to put the guts into a wireless sega genesis controller, but I doubt I'll ever get around to it.
The phone has tv-out, so it isn't a bad setup if you're stuck in a hotel room with time to kill.