Irwin Lazar's "Real-Time" Blog: The Age of Real-Time Communication, Presence and Collaboration is Here!: "Om Malik reports in his blog on the announcement of 'Tello', which is a service designed to bridge the gap between various forms of communication (IM, voice, mobile) by enabling the sharing of presence information between systems. Tello is the brain child of Jeff Pulver and is backed by an all-star team of individuals including Craig McCaw and John Scully. "
See Irwin's post for links and more insights.
(And never underestimate Craig McCaw...)