WinUAE 3.0 with PowerPC Support
Toni Wilen has released WinUAE 3.0 that adds support, among other things, for PowerPC support. This does enable the ability to run Amiga OS 4.0 PPC, AmigaOS 4.1 Classic PPC, and likely AmigaOS 4.1 Final Edition under emulation.
You can download WinUAE from the WinUAE site.
Note: You will need copies of Blizzard or Cyberstorm PPC ROMS and the rom image for a Picasso IV. Please obtain those legally.
Support for WinUAE is on the English Amiga Board, here.