I have introduced some Free iPhone Icons for developers and A huge collection of icon sets for designers some weeks ago.
punypng is a free tool that dramatically reduces page load times by reducing the file size of an image without any loss of quality. punypng uses several web optimization techniques to reduce the file sizes of your images. It first analyzes the content of your image and figures out the best image format to use.
Depending on the file, punypng will automatically convert your GIF into a PNG format and then further compress that. For JPEGs, sometimes it’s better to make it a PNG, and other times it’s better to keep it as JPEG and use jpeg-tran to optimize it. punypng makes all those decisions for you and ensures the best possible results.
License: License Free