When I first mentioned that US News and World Report's latest cover emphasis dealt with The Power of Prayer and What People Pray For, I only had access to an emailed portion of one of the articles. (The online links weren't working for me.) I just read the magazine and both reports (along with the two sidebars) are fascinating...and truly fair to people of all religious persuasions.
Check out the following links:
The Power of Prayer
How We Talk to God
Results of Polling on Prayer
Beads and Blessings
The best book on prayer, so far as I'm concerned was written by Ole Hallesby. Called simply Prayer, it can be purchased from Augsburg Fortress Publishers.
If you're interested in learning more about what scientific studies are showing about the impact of prayer on medical conditions, I would suggest: Healing Words by Dr. Larry Dossey.