Not really, but there's something just a little wrong about using an iPhone app to roll your dice. And that's just what my friend Colin did in a D&D game last weekend. He insisted on it, even when I shoved handfuls of dice under his nose. In fairness, he relented and rolled polyhedrals later in the evening—after his iPhone's battery started to die.
Here's the group shot. We were actually playing D&D 4e—a first for me, and I'm grateful to Andy (the DM, far right) for putting together a great game for the group, which included one rpg newbie and one fella who hadn't played since high school.
UPDATE: Stargazer notes a couple more dice-rolling apps.