Well, it turns out I singlehandedly constitute the content of the VoxAp carnival on the strengths and weaknesses of the ontological argument. I was hoping there would be at least one other entry. But I suppose the ontological argument is not big on the apologetics radar. There has been a bit of discussion here and there in the philosophical blogosphere recently. For instance, Clark at "Mormon Metaphysics" recently posted on Anselm and Marion, and "Fido the Yak" has a post on Gödel's ontological argument. Gödel's argument is a variant of the Leibnizian variant of the Cartesian family of ontological arguments, which I don't discuss in my post. "CADRE Comments" also recently discussed Anselm's ontological argument and Gaunilo's reply. This is a carnival that allows late submissions, so if you want to post and submit something on the argument from a point of view relevant to Christian apologetics, go ahead and do so. There's certainly lots that can be discussed - the Cartesian family of arguments, Thomistic and Kantian criticisms of the argument, Scotus's 'coloring' of the argument, Hartshorne's thesis that the ontological argument shows that either it is necessary that God exist or it is impossible that He exist (which, if true, would surely be relevant to apologetics), etc.
(By the way, this is a tangent, but "Verbum Ipsum" recently had a post on misunderstandings of Anselm's view of atonement; which are legion.)
The next Vox Apologia carnival is on the strengths and weaknesses of the cosmological argument; and, hang it all, all y'all Christian bloggers had better submit something so I can comment on it. The earliest date for submission is April 7; the deadline for making it into the original carnival is midnight, April 10.