Lullabot is proud to present a completely original, completely free iconset: Lullacons Pack 1!
Lullacons Pack 1 includes 113 icons. These general purpose icons fill a basic need in the Drupal (and the open-source community) for visual reinforcement of textual content. Though we intend to use these in Drupal, feel free to use them in any project!
These icons are made to work on any background and in any browser. (Note the 32x32 large icons only work well on lighter backgrounds). They are in 8-bit PNG format, with 1-bit transparency. Worry not about IE compatibility, which has full support for 1-bit transparency in PNGs. IE/Win only does not support alpha-transparency in 24-bit PNGs (but will be supported in IE7). If that was over your head, don't worry. Just rest easy knowing that these icons work in any browser.
Free free free. Not only are you allowed to use these icons for any purpose, you're also granted access to the original Photoshop .psd files. These are licensed under the GNU General Public License. This license means that you are granted full rights to modify the icons however you feel. However, if you use these icons or the source files as the base for your own new icons or iconset, you also must make your modified source files available upon request. If you're feeling particularly generous, we'd love to publicly host your derivatives of the Lullacons along with the originals.