Hey cool! I think we should do it again. How do you make avatars?

Got any photo-editing software? GIMP? Photoshop? Some nice photos and a few images in your head you want to turn into something others can see? A basic tutorial can give you enough understanding of your software to be able to do the vast majority of different effects. There's also a lot of open source pictures online so you can literally make any image you can imagine. Seriously... it's incredibly simple if you have the software and that doesn't need to be expensive (I use open source so it's free).
There's far more information available out there, but I'm 1/2 asleep so... Honestly, the easiest way to figure it out is just to play around with the tools you have/can get for free. Folks here can help you resize it to fit the guidelines afterwards.