Ralph Jenson and I built us a pretty-darn-close-to-perfect copy of Vonage back a couple years ago and were within a whisker of kicking it off here in the Twin Cities. Unfortunately, Vonage came to town a year earlier than we thought they would and blew us out of the water. But I've been tracking VOIP stuff ever since.
These days the most interesting thing to me is the regulatory rasslin' that's going to be going on, so this will mostly be policy-wonk stuff. Heck, I've got to give a speech about VOIP regulatory impacts in a few weeks. That research alone should fill up several good blog entries.