You can find some nice free icon sets from DryIcons.com, the icons are carefully designed and developed by a team of professional web and graphic designers. They designed the DryIcons website to bring your applications the best professional appearance. All of their icon sets contain icons commonly available in 16×16, 24×24, 32×32, 48×48 pixel 32-bit transparency PNG format and 128×128 pixel Photoshop’s PSD image format.
All DryIcons are licensed under a Creative Commons Attribution 3.0 License. This means that you can do pretty much everything with our icons and use them in any personal or commercial projects. However, you must include a link back to http://dryicons.com/ in your credits. I particular like the following sets of icons.