What is the Ezekiel War Theory? I was watching an Evangelical thriller movie the other night (Jerusalem Countdown) which was an apocalyptic film that centered around the Ezekiel War Theory. 

What is this theory exactly? From what I gathered it mentioned something about Russian and Iran nuking Israel? But where in Ezekiel do they support this? 

Is this theory regularly taught in some congregations?
John Hagee, the author of the book Jerusalem Countdown that forms the basis of that movie, is a dispensationalist, non-denominational pastor.  His book follows in the tradition of Hal Lindsey's The Late, Great Planet Earth, and both rely on a dispensationalist understanding of the Book of Revelation and OT prophets in order to predict the future.
Most relevant here, the story of Gog and Magog in Ezekiel 38 and 39 plays a significant role.  In it, Israel is attacked by foreign nations, and dispensationalists interpret it as a prophecy that will be fulfilled at the end of the age. Many seek to identify the protagonists with modern nations: like other Cold War-era dispensationalists, Lindsey identified the Soviet Union with Gog and Magog, while more recent authors, like Hagee, see a connection with modern Islamic states.
Hagee has gained some notoriety for some extreme views and how vocally he shares them.  But on this particular point he isn't far out of the mainstream when it comes to modern dispensationalism.  The Moody Bible Commentary, commenting on Ezekiel 38:5–6, takes a similar approach, though it sees less Russian involvement than Hagee does:

Some interpreters, especially during the Cold War period, inaccurately identified Israel's attackers with the USSR.  The interpretation was based more on headlines and hysterics than hermeneutics and history.
All the countries mentioned here by Ezekiel are today Muslim countries.  Assuming their spiritual allegiance does not change, the future invasion of Israel by these nations will not be a Russian invasion, but an Islamic invasion. The coordination of attack on Israel will not come from Moscow, but from the leadership of these Muslim governments.

So yes, it's fair to say that this sort of thing is commonly taught in churches influenced by dispensationalism.  In the US, that's a significant number, especially among the &quot;non-denominational&quot; churches.