The Power of Prayer in a Believer’s Life - Charles Spurgeon
The Hour that changes the world: A practical plan for personal prayer - Dick Eastman
Praying God’s Word - Beth Moore
Too busy not to pray: slowing down to be with God - Bill Hybels
Fresh Wind, Fresh Fire: what happens when God’s Spirit invades the heart s of his people - Jim Cymbala
http://www.prayertoday.org – many good resources to download
http://www.navpress.com/Magazines/Pray!/   Pray Magazine online from Nav Press