ConvertIcon is a website that allows you to convert any image you want (must be .png) to an icon file (.ico), or an icon file to an image file. It creates icons in the following sizes: 16×16, 32×32, 48×48, 64×64 and 128×128. You can either upload an image from your computer or load a remote image by entering the corresponding URL. Click here to go to the website and start converting.
Source: BARRY’S BEST BLOG