How do you get an avatar?
Search Google for them. Or other message boards. When you find one you like, save it to your desktop, then go to your profile, scroll all the way to the bottom, and follow the intructions there for uploading it. Hope this helps, I’d be happy to elaborate if you want me to.
If you have a picture you’d like to use already, you need to attach it to your Chiff & Fipple profile. In “Profile” -one of the options at the top of the screen- scroll down to the avatar control panel, and put the URL for the image you’d like to use in the “Upload Avatar from a URL” box. You’d need to have the image hosted somewhere online for you to do that, photobucket.com is free and easy to use.
Alternatively, you could try uploading an image without having to host it on a seperate site by clicking on “browse” next to the 'Upload Avatar from your machine" box and picking one you have saved to your computer. I’m not sure if that feature is activated on these forums, though, someone else would have to tell you that.
Hope that helps. 
Edit: I replied too late, sorry! 
If you take Chang He’s advice about finding avatars elsewhere, be sure to get permission to use the avatar you find- I know I get touchy when people use my images without asking 
I’m sure there are sites out there that offer pictures that can be used by anyone, but going around and snatching people’s avatars from other message boards might not be a great idea.
Got mine from a free avatar site. There’s a number of 'em.
They had a picture of you on a free avatar site???
If you are into graphics, you can create your own, even animated. You just need to end up with a 100 pixel X 100 pixel image in GIF or JPG format that is less than 20K. Yo can upload it into your profile and it automatically shows up on each and every post you ever made ! 
Whee!
Is avatarity.com free?
Certainly seems so. After all, it is tough to make thumbnail previews of avatars. 