Republican endorsements for Obama

Wayne Gilcrest, Republican Congressman from Maryland
Jim Leach, Former Republican Congressman from Iowa
Harris Falwell, Former Republican Congressman from Illinois
Lincoln Chafee, Former Republican Senator from Rhode Island
Larry Pressler, Former Republican Senator from South Dakota and 1st Vietnam Vet in the Senate
Charles Mathias , Former Republican Senator from Maryland
Jim Whitaker, Republican mayor of Fairbanks, Alaska
William Weld, Former Republican Governor of Massachusetts
Arne Carlson, Former Republican Governor of Minnesota
Linwood Holton, Former Republican Governor of Virginia
Richard Riordan, Former Republican Mayor of Los Angeles
Fred Bramante, Former Chairman of New Hampshire Board of Education and Huckabee co-chair Susan Eisenhower, International security consultant and daughter of Dwight Eisenhower
Joel Hagen, current Republican candidate for Congress in Oregon
Colin Powell, George W. Bush Secretary of State, George H.W. Bush National Security Advisor
Scott McClellan, George W. Bush Press Secretary
Doug Kmiec, Ronald Reagan and George H.W. Bush head of legal counsel
Larry Hunter, Reagan and Bush economist
Charles Fried, Reagan solicitor general
Francis Fukuyama, former advisor to Reagan
Ken Adelman, member of Ford, Reagan, and Bush administrations
William D. Ruckelshaus, Nixon Deputy Attorney General
Jeffrey Hart, Nixon and Reagan speechwriter
Tricia Mosely, Strom Thurmond staffer
Tony Campbell, Congressional staffer and former Republican candidate for Congress
Jackson M. Andrews, Counsel to Senate and former Republican candidate for Senate
Rita Hauser, Former George W. Bush intelligence advisor
Andrew Bacevich, Boston University International Relations professor
Andrew Sullivan, Conservative author
Tom Bernstein, Texas Rangers owner and Bush supporter
Julie Nixon Eisenhower, daughter of Richard Nixon
C.C. Goldwater, granddaughter of Barry Goldwater
Lilibet Hagel, wife of Republican Senator Chuck Hagel
Christopher Buckley, Conservative columnist and editor, son of William Buckley
Wick Allison, Conservative editor and former National Review publicist
Major General Walter Stewart, Former Commander of Pennsylvania National Guard
Elizabeth Drew, author of Citizen McCain
Nicholas P. Cafardi, Catholic legal scholar and former dean of Duquesne University School of Law Dennis Hopper, Conservative actor and filmmaker
Michael Smerconish, Conservative talk-show host and lawyer
Bill Handel, Conservative talk-show host and lawyer

Even more endorsements here that I haven't managed to add yet