I have had some questions regarding the icons (or rather images) that I use in my applications (such as the 'pending' Mini SQL Query tool)...
They are by Mark James - he has a bunch of great free stuff available at:
http://famfamfam.com/ - more so the "Silk" set at http://famfamfam.com/lab/icons/silk/
The images are licensed under a Creative Commons Attribution 2.5 License.