Arizona Republicans are casting their votes for the 2012 GOP primary tonight, with polls closing at 9:00 p.m. EST.

Former Massachusetts Gov. Mitt Romney, former House Speaker Newt Gingrich, Texas Rep. Ron Paul and former Pennsylvania Sen. Rick Santorum remain in the race, but with Newt Gingrich avoiding the state and Paul is last place, the contest in Arizona, like that in Michigan, is a essentially a two-man competition: Mitt Romney vs. Rick Santorum.

Mitt Romney is currently ahead in Arizona with 42 percent support. Rick Santorum is in second with 29 percent, followed by Gingrich with 16 percent and Ron Paul with eight.

The 2012 Arizona Republican primary is a winner-take-all contest, with all 29 delegates going to the first-place finisher. The state originally had 58 delegates, but the Republican National Committee penalized it for violating party rules and holding the primary before March 6.

For those who want to track each candidates' progress in the Arizona GOP primary, have no fear: CNN and other news sources will providing live coverage of the primary results for both Arizona and Michigan.

Other political news organizations and blogs began posting up-to-date live blogs before the polls closed.

Below, find out where to watch live-streamed results and reactions on the ground in Arizona, and how to get live updates on everything about the primary, from Twitter reactions to the candidates' speeches.

When to Watch:

Arizona polls will close at 9:00 p.m. EST (7:00 p.m. MST) tonight. Results are expected to come in starting around 9:15 p.m.

Where to Watch:

CNN will provide live coverage of both the Arizona and Michigan primaries beginning at 6:00 p.m. EST.

POLITICO's live coverage of the primaries will begin at 6:30 p.m., while MSNBC will start giving live updates at 8:00 p.m. EST.

Where to Get Live Updates:

The Washington Post and The Huffington Post will both be hosting live blogs of the Arizona and Michigan primaries.

POLITICO and Google will also follow the Arizona 2012 Republican primary. Both sites will provide minute-by-minute live updates of which counties are reporting and what candidate is currently in the lead.

How to Follow the Primary on Twitter:

Use #AZPrimary to join the conversation about Tuesday's election on Twitter. CNN is also sponsoring the hashtag #cnnelection, bringing users live updates from its Twitter page @CNNPolitics.