WebAppers is going to release a set of beautiful web application icons, they would be free for both personal and commercial use. These icons are currently under development, and will be released in the next 2 – 3 weeks. Please stay tuned. At the moment, you can have a look at the following three sets of glossy and modern icons available at deviantART first.
Feel free to use these Colourful Pie Chart Icons. They are licensed under Creative Commons Attribution 3.0. The sizes of the icons are included: 512, 256, 128, 64, 32. Please do not use these icons on illegal and unpleasant activity (example; porn, warez, hacking, anti-religion, racism, etc).
The name says HP Dock Icon Set but it’s really not HP themed. I just used the colours and such from the monitor icon. They are licensed under Creative Commons Attribution-Noncommercial-No Derivative Work 3.0. The sizes of the icons are included: 1024, 512, 256.
You are free to use Pandora Icons for personal use. However, if you intend to use these icons for a more corporate use (skins, etc) then please PM the author with the request, letting him know what you want to use them for. Also, author would appreciate a credit for the work, and a link back.