ephemeron
Explorer
There used to be portraits on the D&D site, but now with google just a few keystrokes away portraits are easier than ever to find. Which is not to say they're particularly easy, just that it's better than it used to be.
At least some of the old portraits are still on the D&D site moved to http://archive.wizards.com/default.asp?x=dnd/arch/pc. There are also some new ones at http://dnd.wizards.com/articles/features/character-portraits.