The easiest way to install Front Row on non-IR Macs doesn't require even Pacifist.
Just like the previous post explained how to check which models it supports, you just need to right-click on the FrontRowUpdate1.2.2.pkg and show package contents, then Contents, then open the FrontRowUpdate1.2.2.dist with Textedit. Navigate to where it says what models are supported. (e.g. "PowerMac12,1"
Going to 'About This Mac', then 'More Info' on your computer will show your model. (e.g. My Dual 1.8 G5 is PowerMac7,3)
Just replace one of the models in quotes in the .dist file in Textedit with your model, save, then run the pkg as usual. Simple. Make sure you take the package out of the disk image though before you try to edit the dist file, because sometimes it won't allow you to save the file if it's still on there. Just put it on your desktop before starting.