I was going to suggest the Signature Generator we posted a while back if you wanted to post a much more detailed look at your characters on Facebook or anywhere else, but apparently it's MIA. The site doesn't load at all. The Google cache shows that maybe the site's creator burnt a bridge he wasn't supposed to, and unfortunately while there are a few other sig generators around, none of them look as good (or work as well-- I couldn't get my character to come up on the other one) as that one did.
So if anyone knows of a good working sig generator, feel free to throw it in the comments below, and we can all show off our characters in our various webspaces. Oh, and though WoW Insider hasn't made our way to Facebook just yet, we are alive and well on Myspace, so come befriend us there if you like.
Update: Reader Nick G sends along his own, self-made Facebook app, which he says is created by a WoW fan, not "a company trying to create a social network website and drive traffic to it via a Facebook App." Which is cool, but unfortunately, when I tried to create my character with his, all I got was an error message. So if his works, you might like it more.