With less than a year to go until the Iowa caucuses, and less than 18 months out from the 2012 presidential elections, the Republican pool of presidential contenders is still uncertain. Earlier this week, Arkansas Gov. Mike Huckabee and real estate mogul Donald Trump announced they would not seek the party's nomination. And pundits are awaiting announcements from big names like Sarah Palin, Michele Bachmann, Indiana Gov. Mitch Daniels and former U.S. Ambassador to China Jon Huntsman.   Among those who've already announced their candidacy, the front runners seem to be Massachusetts Gov. Mitt Romney, Minnesota Gov. Tim Pawlenty and former Speaker of the House Newt Gingrich. Takeaway Washington correspondent Todd Zwillich helps assemble a cheat sheet on the GOP candidates and the big names to watch out for.