Liftoff is anticipated at 3:49pm Saturday...

CNN: Will air a special report, "Shuttle Discovery: Miles O'Brien Reports," from 3 to 4pm. O'Brien, the best space reporter in the business, will be joined by Eileen Collins, commander of the previous shuttle mission. CNN Pipeline will carry the launch live from multiple angles. O'Brien will host a one-hour launch special from 1 to 2pm, and anchored coverage will continue through the launch...

FNC: Martha MacCallum will anchor a special, "Space Shuttle Discovery: STS-121," from Cape Canaveral beginning at 3pm, according to ICN. David Lee Miller will report from the Kennedy Space Center and Kim McIntyre will be in Houston. Former NASA astronaut Tom Jones will provide analysis...

MSNBC: Chris Jansing is reporting from the Kennedy Space Center today, and she'll be covering the launch live tomorrow...

NBC: THR reports: "NBC, which will carry the U.S. Women's Open Championship on Saturday, finalized a plan Thursday that will have NBC Sports throw a few minutes before the scheduled launch to NBC News weekend anchor John Siegenthaler. Joining him will be Tom Costello, longtime space correspondent Jay Barbree, astronaut Steve Robinson and analyst James Oberg..."

ABC: Will begin live coverage at approximately 3:40pm. Bill Weir will anchor from New York with Ned Potter alongside. "Lisa Stark will report from Kennedy Space Center in Florida with NASA Astronaut Catherine 'Cady' Coleman..."

CBS: Will broadcast the launch. "The live coverage will be anchored by Bob Schieffer in New York City. CBS News Correspondent Bob Orr and CBS News Space Consultant Bill Harwood will be live at the Kennedy Space Center in Cape Canaveral, Fla..."