The C64 emulator Frodo for S60 3rd Edition has been updated to version 1.5, and now includes support for accelerometers in selected phones, which lets you tilt the phone to simulate a joystick or steering wheel (you can see a demo video below). There's also an on-screen keyboard and vibration support. Frodo comes in versions available for older Symbian devices too such as S60 1st and 2nd Edition, Series 80 and UIQ, just scroll down the same page. Apparently Frodo for S60 3rd Edition should work in theory on the 5800, though it may run very slowly as the application hasn't been optimised for S60 5th Edition yet. (For more S60 3rd Edition emulators, see AAS's special feature.)

Here's Frodo's accelerometer support in action on a Nokia N95: