An avatar is your online representation of who you are.  Good rules of thumb - Never use your entire first and last name - it is much better to use just your first name and some numbers.  Also, never use a real image of yourself that someone could identify you from. 

WEBSITES 

Become a M&M's Character

http://www.mms.com/us/becomeanmm/   

BuiLD YouR WiLD SeLF

http://www.buildyourwildself.com/ 

Wee World

http://www.weeworld.com/ 

The Hero Factory

http://www.cpbintegrated.com/theherofactory/

Yahoo Avatar Creator

avatar.yahoo.com/

Manga Avatar Creator 

http://www.manga.com/content/avatar-face-maker

TO DOWNLOAD

Downloadable SWF file to create avatars -  avatars.swf

Instructions: Right-click the above and save to your computer.  When you open it - right click the file and choose Open With - then choose Firefox or IE.  When you have finished creating you will need to take a screenshot (PrtSc or SnagIt) and then save as a jpg.  Don't forget to resize it also.  200x200 pixels is a more than enough for most sites.