http://illustmaker.abi-station.com/index_en.shtml

I found this link in my bookmarks.  You can make icons/avatars with it.  There is a page there that talks about terms of use.  You can use them on discussion boards. 

Quite easy to use really.  Just plug in numbers and generate an avatar. Save to your computer when you are done.

If you go to the bottom of the page where you are making the avatar, there  is a menu where you can look to see what the different looks/styles are.

Here is the main link which has some more options:

http://abi-station.com/

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi