The avatar that I created at Meez.com is displayed above. Meez. com is a lot more sophisticated than Yahoo. Yahoo only allows you to display your creation on its products; whereas, Meez permits you to export your avatar to numerous places. Also, with Meez, you can let your imagination run wild in terms of hair, face, dress, backgrounds, etc. I had fun and could have spent a lot more time playing.
I also googled the term "online image generator." There are a lot of free generators available and you can create a variety of things (avatars, buttons, barcodes, logos, etc.) Below is a logo that I created for my blog.