I am sharing my very first and very (un)useful point with you.
If you would like to change the green spinning waiting icon:
This icon can be found in the template\images directory of your 12 hyve (C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\IMAGES) and is called GEARS_AN.GIF.
Just rename this file (in case you need to go back to original version), rename your own image to GEARS_AN.GIF and place this image in the template\images directory of your 12 hyve.
See the example bellow:
