Wiimpathy got his hands on Hatari 1.9.0. Hatari Wii is an Atari ST(E), TT and Falcon emulator. This emulator comes with EmuTOS which is a free and legal replacement for the actual required TOS, but you can replace it anytime with TOS 1.02 or 1.04 for ST games, and TOS 1.62 or 2.06 for STE games. Tos 3.0x are for TT, and 4.0x are for Falcon (untested in the Wii version).

Go ahead and enjoy Atari ST on your Wii!