Simone Bevilacqua released glUAE for AmigaOS4. This system makes emulation of the classic Amiga very easy on AmigaOS4. You can now start a game by a simple double-clicking on an icon. You can use one or many applications at once or have a whole classic AmigaOS system installed on a partition or in a directory. Visit the glUAE web page for more details.
Demonstration of glUAE on YouTube.