1. Choose one of your friends' icons.
2. Photoshop a santa hat onto it; as badly as you like.
3. Er... that's it.
First batch below; if you're still using last year's icon and I've behatted it before, I probably won't have done it again. If you're feeling left out, or I did the wrong icon, then comment and I'll do one over the next few days. Edit: I forgot to upload some of them! They're here now.