MOCpages user, Michael Taylor creates the famous Superman symbol in Lego mosaic form.
I personally am not really a superman fan, so you can view his Batman and Spiderman symbols here (Woo! Batman!). You can also view a Lego comic book specific blog here. ComicBricks, run by Bruce N H.
* Edit - Hahahahaha, looks like Bruce beat me to the punch for blogging this...go (mini)figure.
** Thanks to Katie Walker for sending me the link to the mosaic. If you have a mosaic you want to see featured, email me at mosaicbricks (at) gmail.com