Daniel Berninger wrote the most informative article about Voice over IP I've ever read, over at Om Malik's blog. It outlines in great details the history behind the evolution of traditional communication technologies framed within the convergence of various Internet-related technological advances, and the challenges PSTN telcos are facing to hold-on to their shares of this lucrative pie. Beyond mere technological issues, Berninger offers great parallels and insights on past, current, and future governmental regulatory policies. A must read for anyone who's ever talked on the phone.
Daniel's article sheds additional light to some of the thoughts I've outlined in this blog entry.