Well, all you have to do is write something having to do with Webkinz in your siggy and color it, then you get a Webkinz avatar! You could also put the name of your Webkinz in your "Intrests" section in your profile.
Like I said to Piggy950623, here's how you get a good pic for your Webkinz avatar:
Just go to Webkinz.com, click on "Webkinz Catalog" and click on the Webkinz you like best and either save the stuffed animal picture, the online Webkinz animal, or the item that you want to be your avtar (right click save) and then upload it when you change your avatar.
You don't have to do this, but it would be cool if all us Webkinz lovers could have a Webkinz avatar!