As of this date (April 7, 2006), the TOC website sections indicate that both Nathaniel Branden and Barbara Branden will be presenting, plus Q&A in the Objectivist Oral History project (see the posted schedule).
Plus a shameless plug - if you have not yet heard the CD 20-lecture set, Basic Principles of Objectivism, please do so. It is a masterful tour de force, elegantly and forcefully presented. Available through TOC, I might add.