Outside at Lincoln Center, prior to the Walter Cronkite memorial service.

At this hour, a veritable who's who of journalists, political figures, and other newsmakers are either on their way to Avery Fisher Hall at Lincoln Center in New York — or have arrived there by now — for the public memorial service for legendary CBS newsman Walter Cronkite.

TVNewser editors Chris and Kevin are on the scene, and have spotted CBS's Les Moonves, Bob Schieffer, Morley Safer, Bill Plante, Rick Kaplan, Jeff Greenfield, and Erin Moriarty; former CBS News president Andrew Heyward; NBCers Steve Capus and Brian Williams; ABCers Diane Sawyer, Charlie Gibson, and Barbara Walters; and former The Insider host Pat O'Brien.

Attendees were asked to arrive early for the 10:30amET service "due to security concerns surrounding the appearance of President Obama at this event," according to a CBS press release.

President Obama has left the White House en route to the service, where he is scheduled to speak, along with former President Bill Clinton, former astronaut Buzz Aldrin, and others.

CBS will stream live coverage of the service on CBSnews.com, CBS.com, TV.com, and other sites as well. Chris and Kevin are providing updates today on Twitter, and will have a full report this afternoon.

Walter Cronkite passed away at the age of 92 on July 17.

> Update: Live streaming has begun at cbsnews.com. Spotted in attendance: Katie Couric, Dan Rather and Andy Rooney. Joanna Simon, who had been Walter Cronkite's companion in the last few years, is also there.