Here are all of the Icons for the mane 6 that I have created.
Contained in the ZIP file are all of the icons above with and without backgrounds in PNG format.
Feel free to use them however you want.
If you redistribute them in any way credit would be appreciated.
Apparently this was featured as a daily deviation on 6/22/2013.
Edit: Remade the Applejack icon.
Edit 2: Remade Fluttershy Icon.