Since I needed a little more image polishing power than iPhoto could give me (even though it's really killer) and since Adobe apparently won't have a Universal version of Photoshop until early next year, I started a search for a tool that could fill the gap.
I had heard about Gimp years ago from my brother-in-law back when it was only around for linux. Since then there have been ports to Windows and Mac OS X. Of all the freeware tools available, it seemed to be pretty popular and have a good following. I was pretty close to downloading the app from here, when I stumbled on a build of Gimp called Gimpshop.
Gimpshop's claim to fame is that it has been reworked a bit so the UI more closely matches that of Photoshop as well as a lot of quickkeys. (To install Gimpshop, you will first need to install the X11 package which is on the OS X Tiger install DVD.)
The set up was pretty easy and before too long I had Gimpshop running. I didn't play with it too long but quickly I realized that the UI is similar to Photoshop's best. But all the major tools that I need seem to be there: I can make and edit layers, I can change layer transfer modes, I can make layer masks, I can appy blur filters, I can remove defects with a rubber stamp tool, etc.
For now, at least, Gimpshop seems to fit the bill.
I messed around with Gimp many moons ago in pursuit of a lightweight/free tool for developers who want to make minor image tweaks without having to track down a PS user/owner. Most of these developers were linux boys so they got an extra happy out of Gimp. I'll definitely check out Gimpshop - thanks for the tip!