This book covers this subject in some details.  Here are some reviews from Amazon;

Keenly observed and meticulously reported, God's Profits examines the unholy alliance between a new breed of corrupt televangelists and the Republican Party, which is eagerly courting "values voters" in the nation's largest megachurches.
Author Sarah Posner exposes the activities of Kenneth Copeland, John Hagee, Rod Parsley, T.D. Jakes, and other politically connected, skillfully marketed, and increasingly influential religious leaders. Preaching the "prosperity gospel"--the notion that faith and tithing alone can ensure financial security--both in their churches and over the airwaves, these charismatic leaders scam the gullible even as they enjoy unprecedented access to top Bush Administration officials.

Admired by Republican strategists for their antigovernment ideology and authoritarian leadership styles, these televangelists work together to maximize profits; protect themselves legally; influence elections, judicial nominations, and promote their pro-war, apocalyptic ideas.

From the Back Cover
* GOD'S PROFITS is is a fascinating and important investigation into the sordid nexus between religious zealotry and run-amok capitalism. Sarah Posner has given us a vivid account of a new generation of spiritual hucksters whose venality is nearly matched by their political influence. The story she tells is appalling, but the way she tells it is enormously compelling. --- Michelle Goldberg ---

* Sarah Posner has produced the definitive expose of America's leading "prosperity gospel" preachers. With direct access to the Bush White House and Republican lawmakers, these televangelists have injected their Armageddon-based agenda into US. foreign policy. Posner's book should serve as a stark warning to anyone tempted to dismiss the John Hagees and Rod Parsleys of the world as benign loons. --- Max Blumenthal ---

* Sarah Posner's reporting on the religious right is dogged, informed, and ceaselessly illuminating. She never condescends to rank-and-file believers; at the same time, she never excuses their leaders' hypocrisies or fundamental misunderstanding of, and threat to, our constitutional republic. --- Michael Tomasky ---

* Sarah Posner introduces us to the stars of a new evangelical movement who have declared welfare Satanic, poverty a religious curse, and redistribution of wealth "contrary to the word of God." GOD'S PROFITS serves as an urgent warning about their toxic and corrupting effect on American politics. --- Esther Kaplan ---

* GOD'S PROFITS is an astounding tale of religious hucksterism--and its role in politics--as big and crass as the ostentatious empires of the Word of Faith movement itself. It features a cast of charlatans, demagogues, con men, and the pols and presidents who pander to them. It is also a window on the rise of the Bush family dynasty and details how John Hagee, Rod Parsley, and their ilk treat faith as a cheap political commodity on its behalf. --- Frederick Clarkson ---