Instantly Customizable Icons: Iconza
Iconza is a free icon set which can be customized instantly with the help of a web-based application.
Users can choose any color, background color & size (16*16px, 24*24px or 32*32px) for the icons. After that, whole set (PNG files) can be downloaded as a ZIP file.
The set has 70 icons & covers the most popular ones that can be used in web applications like actions, arrows, users, e-mail, RSS & more.