You don't need CandyBar(The program) to change your application icons. And here's why you don't need it:
Step 1// Make the design. (For this tutorial, I'll make it for iChat)
Note: Be sure the background is transparent. I use 2 by 2 inches, 180 dpi.
Step 2//Save the file as PNG format.
Step 3//Open the icon you've just designed in "Preview", then copy it.
Step 4// "Get info" on the app that you'd like changed.
Step 5// Leopard might not have this problem, but for the latest Snow Leopard, be sure to change the access for everyone to "Read & Write"
Note: This is only necessary for Apple's own apps. 3rd party apps like Adobe stuff don't require this extra process.
Step 6//Click on the top left icon within the Info box and click paste.
Step 7// Enjoy and repeat from step 1 for all the other icons!
-Benson|| Twitter || the movement|| The Imaginary Zebra website