Updated at 4:27 p.m. ET  Sarah Palin is launching a bus tour of historical sites this weekend in the nation's capital, amid growing signs that the 2008 GOP vice presidential nominee could run for the White House next year.  Palin, a former Alaska governor, says on her website that the "One Nation Tour" is aimed at educating Americans "about our nation's founding principles." No tour stops are posted on the site, but Palin said she'll travel up through New England.  Last week, Palin said on Fox News that she has the "fire in my belly" to run for the White House, but she has not given clear signals about what she intends to do next year. Among other things, she has not done the major fundraising or extensive grass-roots organizing in early caucus and primary states that GOP rivals such as Mitt Romney and Tim Pawlenty have been doing for several months.  "Our nation is at a critical turning point," she explains about the bus tour. "...It's imperative that we connect with our founders, our patriots, our challenges and victories to clearly see our way forward."  Visitors to Palin's website for Sarah PAC are being encouraged to donate and follow the bus tour. There are pictures of the bus, decorated with a huge copy of the Constitution with the words "We the people" boldly depicted and words from the Pledge of Allegiance under the "One nation" logo on the side.  The tour launches Sunday. Palin will appear at the Rolling Thunder motorcycle rally that is part of annual Memorial Day weekend events in Washington, D.C. The rally draws attention to Americans missing in action and honors U.S. servicemembers and veterans.  "She has not been put officially on the program yet, but she's going to come and kick off her historical tour with us," said Nancy Regg, national media chairwoman for Rolling Thunder, Inc.  Regg said details of Palin's appearance are still being worked out because she was just informed about the Republican's tour stop a short while ago. "It has nothing to do with a campaign or anything like that, it's just part of her historical tour that she is kicking off with us," she said.  Among other signs of increased political activity from Palin:  A new Gallup Poll today shows Palin is one of the leaders for the GOP presidential nomination, as the choice of 15% of Republicans and independents who lean to the GOP. She is right behind Romney, the choice of 17%.  Palin continues to be a paid contributor to Fox News. The network ended contracts with Newt Gingrich and Rick Santorum as they increased their presidential campaign activity.  "We are not changing Sarah Palin's status," Fox News Executive Vice President Bill Shine said in a statement, reported by CNN.  See photos of: Sarah Palin
Sarah Palin launches bus tour amid presidential talk  - On Politics: Covering the US Congress, Governors, and the 2010 Election - USATODAY.com