I used Iconographer X on 10.4 PPC and now started carefully trying it on a 10.5 Intel. Until now it seems to work without problems.
For me Iconographer has nothing to do with favicons, which are simple to create. The great thing of the Appp is, that you create your system icon for any File or Application a very flexible way: You can create different sizes for the Icon (let's say a big Verison - more detailed, with text and a small Version - simpler, without text), each size with own Mask (Alpha Channel). Then you save it in a file and see the result: Depending on your display preferences, OS X chooses the appropriate icon size. Fine, but it gets better: You can also create Windows icons for 95/2000/XP (For this software has not been continued for some good time, there unfortunately is no support for the bigger Vista Icons).
So when I create a Flash Game and burn it on a CD for both Mac and Windows, Iconographer helps me to make it look professional with perfect Icons.

I am very sorry that Iconographer has not been continued. I do not know an alternative, so I keep on using it - it is a great piece of software.