MimiGlyphs has provide a nice set of 80 slick pixel-perfect icons that you can use in your web applications for free. The set comes in .PSD and .CSH (custom shape Photoshop) edit file types but also in transparent PNG format (16px*16px).
The pack includes icons of actions, charts, comments, devices, social networking and other types. The pack is free and can be used in both comercial and personal projects.
MimiGlyphs: 80 pixel-perfect web icons: Preview