How technology has advanced!
Very soon, technology will involve conversation beyond what normal conversation offers - think simultaneous manipulation of something, such as virtual sketchpads for everyone in an IM conversation but on a more creative level. However, nothing beats face-to-face if possible, which is probably the irony of the statement. Phones are used to arrange face-to-face meetings with people - is this the future of phones?
As for IM, it's going to last as long as IRC if not longer. I consider it a seperate methodology from face-to-face as there are some things neither can replicate on each other.*