Nope. Parallels is Intel only. However, Virtual PC is for PPC Macs.

There is an application under development called Darwine that runs Windows Applications, but it isn't able to run exe files under PPC Macs yet.

There is a way to run .net applications on Mac OS X. See here. I'm not so sure if this will work for you, but I heard that you might be using .net. Not sure yet...

I believe there are a few incompatibilities between Mono and the .NET framework. So in my understanding, projects have to be targeted to Mono to run under it (it doesn't just run .NET stuff). However, if the source code was released, it'd be a fairly easy port.

Well, the source code will be released so if anyone wants to port it to Mono it shouldnt be too difficult. If anyone wants to do this they should PM me. Its written in C# using .NET 2.0.

As for the undo feature, the obvious way to implement it would be to just use a stack and a Command object implementation for all actions. Thing is, you cant just hold onto all the actions the user makes, because that would take an unbelievable amount of memory after a few hours of hacking. So there needs to be a happy medium where once the user goes beyond like 50 actions, it dumps the first action and then continues buffering new actions. I might have to write a custom stack class for this so that I can easily remove from the bottom of the stack.

Good idea. It should be in between 1 and 255, with 255 being the upper 8-bit integer limit.

You might not have graphics editing in there as a final, but what about a way to decompress the graphics? That would be very useful...