Use the official websites for Presidential information. Use the Senatorial/Congressional websites for voting records, etc.
Democrats:
First Tier Candidates for the Democratic Party:
Senator
Hillary Rodham Clinton of New York
Official Website:
http://www.hillaryclinton.com/?splash=1
Senatorial Website:
http://clinton.senate.gov/
Senator
Barack Obama of Illinois
Official Website:
http://www.barackobama.com/
Senatorial Website:
http://obama.senate.gov/
Former Senator
John Edwards of North Carolina
Official Website:
http://johnedwards.com/splash/
Second Tier Candidates:
Governor
Bill Richardson of New Mexico
Official Website:
http://www.richardsonforpresident.com/
Gubenatorial Website:
http://www.governor.state.nm.us/index2.php
Senator
Joe Biden of Delaware
Official Website:
http://www.joebiden.com/
Senatorial Website:
http://biden.senate.gov/
Senator
Christopher Dodd of Connecticut
Official Website:
http://www.chrisdodd.com/
Senatorial Website:
http://dodd.senate.gov/
Third Tier Candidates:
Representative
Dennis Kucinich of Ohio
Official Website:
http://kucinich.us/
Congressional Website:
http://kucinich.house.gov/
Former Senator
Mike Gravel of Alaska
Official Website:
http://www.gravel2008.us/
Potential notable candidates:
Retired General
Wesley Clark of Arkansas
Former Vice President
Al Gore of Tennessee
Republicans:
First Tier Candidates for the Republican Party:
Former Mayor
Rudy Giuliani of New York City, New York
Senator
John McCain of Arizona
Former Governor
Mitt Romney of Massachusetts
Second Tier Candidates:
Senator
Sam Brownback of Kansas
Former Governor
Mike Huckabee of Arkansas
Representative
Duncan Hunter of California
Former Governor
Tommy Thompson of Wisconsin
Third Tier Candidates:
Former Governor
Jim Gilmore of Virginia
Representative
Ron Paul of Texas
Representative
Tom Tancredo of Colorado
Potential notable candidates:
Former House Speaker
Newt Gingrich of Georgia
Senator
Chuck Hagel of Nebraska
Former Senator and actor
Fred Thompson of Tennessee
Constitution Party:
Actively pursuing or interested in candidacy for the Constitution Party (United States):
James Gilchrist of California
Dale Thompson of Kentucky
Green Party:
Elaine Brown of Georgia
Kat Swift, co-chair of Texas Green Party.
Alan Augustson of Chicago, Illinois
Individuals frequently mentioned as possible candidates:
Ralph Nader of Connecticut (rumored candidate. A "Draft Nader" effort has begun among some Greens.)
Former Representative
Cynthia McKinney of Georgia
Rebecca Rotzler of New York
Libertarian Party:
Official candidates who have filed with the FEC for the Libertarian Party:
Mike Jingozian of Oregon
Bob Jackson of Michigan
Steve Kubby of California
George Phillies of Massachusetts
Christine Smith of Colorado
Actively pursuing or interested in candidacy:
Barry Hess of Arizona
Robert Milnes of New Jersey
Wayne Allyn Root of Nevada
Independents:
Official candidates who have filed with the FEC as independent candidates:
James H. Mccall of Ohio
Donald K. Allen of Ohio
Steve Adams of Kentucky
David Koch of Utah
John Taylor Bowles of South Carolina
Individuals who have expressed serious interest
David J. Masters of North Carolina
Individuals rumored to be considering a presidential run:
Mayor
Michael Bloomberg of New York City