I found this announcement at Kurzweil's web site:

Wolfram|Alpha will be an amazing product, but as a "computational knowledge engine," it's quite different from Google and other search engines.

Alpha, however, will probably be a worthy challenger for Wikipedia and many textbooks and reference works. Instead of looking up basic encyclopedic information there, users can just go to Alpha instead, where they will get a direct answer to their question, as well as a nicely presented set of graphs and other info.

Stephen Wolfram's first public presentation of Wolfram|Alpha will be at Harvard Law School on Tuesday, April 28, 3:00 EDT. If you cannot attend the presentation in person, the live webcast may be an option.

The webcast should run there.