As I was surfing around last night before heading out for Dine Out For Life, I came across this great website that has the official RSS Feed Icons. It's a ZIP file that contains not only the PNG files, but also JPG, GIF, PSD and several other formats, so you can customize them to your hearts content.
If you're not familiar with them, they were originally created by the Mozilla group, and when it came time to pick icons for IE7, Microsoft jumped on the standards bandwagon (as seems to be the general principal for IE7 (yay!)), and they standardized on the same icon. Inside the ZIP file, is a short PDF about the history and use of these icons, it's worth checking out.
Now, it's time for me to update all my websites to use the new standard icons.