Think [Tap-Dance] God

Here is some stuff on the ontological argument:

• This article by philosopher Alex Byrne contains the best explanation of the ontological argument I've read.  Here's another good one.
• the Stanford Encyclopedia of Philosophy entry
• the Internet Encylopedia of Philosophy entry
• the entry on St. Anselm
• Logician and mathematician Kurt Gödel came up with an impressive version of this argument based on modal logic.  Check out a formalization of it below.