The Mac OS X 64-bit compiler is installed by default. Instead of calling "fpc", you need to call "ppcx64". You should generate a Univeral Binary using lipo. (For an example, take a look at a shell script I posted some time ago)

I think some hardware acceleration on Mac OS X through Cocoa's drawing API is available, as I sincerely doubt it's all CPU-dependant, because it's just a difference of 370 MhZ on each core between my MacBook Pro and my MacBook.