There are thousands of free icon collections out there. Most of them are oldies or full of spam and popups.
Today, I´ve discovered the best free icons web site Ive seen.
* It has thousands of icons
* They are categorized
* The download links aren´t one thousands clicks away
* Most icons are pretty new, with an excellent quality and HiRes
Be careful with the copyright of some of them if you are going to use them in your projects.