CTAP2.0 suggests using Yahoo: "4. Create an avatar -- a representation of yourself. Go to http://avatars.yahoo.com/ , design an avatar [representing you or a younger version of yourself] with a school, library, or classroom background. (You will have to set up an account if you don't use Yahoo!) Save your avatar and export to your blog." They give you directions on how to export. The Yahoo site is nice because there are tons of options. However, you cannot create an avator from this site at school. You can do a Google search and find lots of programs. The following 3 are quick and fun and best of all, you save them in your picture folder.
On the last post, I suggested using Portrait Illustrator Maker. This site is easy to use and has lots of options (you can even include wrinkles if you wish!). http://illustmaker.abi-station.com/index_en.shtml
Another really easy site to use is DoppleMe http://doppelme.com/. You have to registar, but it is free. This one was very quick.
The students suggested using The Stacks from Scholastic (designed for students, but fun to use). https://my.scholastic.com/sps_my_account/accmgmt/FlashLogin.jsp?finalSuccessURL=http://kids.scholastic.com/community/my_profile.htm
I still like http://www.voki.com/. It's a great attention getter. This is the Voki that I created that made an announcement for my students.