Well first of all you need an avatar. So you pick a picture you like, make it a decently small size so it doesn't take over the whole page (like about 25kb or so) then you have to host it on a website. If you have telus or shaw, they give you some webspace, if not then you need to find someone with webspace to host it for you.
A URL is basically the address that a webpage is given. It usually starts with "http://" so in order to post your avatar you need to post the URL of the webpage it is on.
If you don't have any webspace, send me the avatar you want and I can host it for you.
Christy
