First on TVNewser: NBC News chief White House correspondent David Gregory is being tapped to anchor a new MSNBC program called Race for the White House. Gregory will take over the 6pmET time slot from Tucker Carlson who remains with the network as MSNBC's Senior Campaign Correspondent, reporting for all MSNBC shows.

Gregory, who will continue reporting on the Bush White House and filling in for Matt Lauer on the Today show, will anchor the MSNBC program from NBC's Washington Bureau.

Gregory joined NBC News in 1995 as a correspondent for NBC Newschannel. He moved to MSNBC in 1998 to host daytime programs including Crosstalk NBC. Gregory covered the campaign of George W. Bush in 2000 and became White House correspondent when President Bush took office.

This is just one of the changes to MSNBC's lineup. Others, including changes for Countdown, after the jump...

• NBC's Andrea Mitchell becomes the anchor of MSNBC's 1pmET program...

• Live with Dan Abrams re-launches as Verdict with Dan Abrams...

• Countdown with Keith Olbermann will now re-air at 10pmET (it had been re-airing at MidnightET)...

• The Doc Block moves back and adds a third hour. It will now air from 11pmET-2amET...

• Countdown gets a second re-air at 2amET...