Dear Anthony:

Many Pentecostals belief in the notion called Positive Confession. . This is more popular known and the "claim it and name it" Gospel. This is part of what is called the Word of Faith movement founded by Evangelist E.W. Kenyon (1867–1948). Kenneth Copeland and Benny Hinn are contemporary examples of this movement. The is a video, Suffer the Children, that explores teachings, including heretical teachings of the Positive Confession movement.

The origins of this movement go back to the metaphysical cults, such as Phineas Quimby's New Thought Movement (that teaches that true human selfhood is divine, divine thought is a force for good, sickness originates in the mind, and "right thinking" has a healing effect) and Mary Baker Eddy's Christian Science (sickness is an illusion that can be corrected by prayer alone). 

A.B. Simpson and A.J. Gordon of the Faith Cure movement were major influences upon E.W. Kenyon, founder of the Word of Faith movement.

These people believe they can speak health into existence. If physical healing does not take place they teach that in the spirit they have been healed. This is also applied to prosperity and wealth. It is believed that illness (or poverty) is the devil's way to rob the faithful from the health (and prosperity) that is there Godly right.

A very large problem with this theology, other than it is wrong, is that if one speaks the word of faith for healing and they are not healed they poor soul thinks that it is because he did not have enough faith. The language of the preaching and of the adherents encourage this self-doubt, even though they say they have done no such encouragement.

This theology also denies the grace and virtue of suffering and deny that sickness and poverty can be good, in direction opposition to Roman 89:28 where St. Paul says that, "All things work together for good..." and may other passasges where we are to praise God for our afflictions.

Some in this movement include heretical teaching of we are "little gods". In the video linked above is a clip of Creflo Dollar teaching this heretical notion to his congregation based upon the idea of "everything reproduces after its own kind".

This is a transcript of this clip:

Dollar: "If horses get together, they produce what?"
Congregation: "Horses!"

Dollar: "If dogs get together, they produce what?"
Congregation: "Dogs!"

Dollar: "If cats get together, they produce what?"
Congregation: "Cats!"

Dollar: "So if the Godhead says 'Let us make man in our image', and everything produces after its own kind, then they produce what?"
Congregation: "gods!"

Dollar: "gods. Little "g" gods. You're not human. Only human part of you is this flesh you're wearing."

GotQustions.org has a good article about this, which includes the following biblical refutation of the Word of Faith movement:

Countering Word of Faith teaching is a simple matter of reading the Bible. God alone is the Sovereign Creator of the Universe (Genesis 1:3; 1 Timothy 6:15) and does not need faith—He is the object of faith (Mark 11:22; Hebrews 11:3). God is spirit and does not have a physical body (John 4:24). Man was created in the image of God (Genesis 1:26, 27; 9:6), but this does not make him a little god or divine. Only God has a divine nature (Galatians 4:8; Isaiah 1:6-11, 43:10, 44:6; Ezekiel 28:2; Psalm 8:6-8). Christ is Eternal, the Only Begotten Son, and the only incarnation of God (John 1:1, 2, 14, 15, 18; 3:16; 1 John 4:1). In Him dwelt the fullness of the Godhead bodily (Colossians 2:9). By becoming a man, Jesus gave up the glory of heaven but not His divinity (Philippians 2:6-7), though He did choose to withhold His power while walking the earth as man.

The Word of Faith movement is deceiving countless people, causing them to grasp after a way of life and faith that is not biblical. At its core is the same lie Satan has been telling since the Garden: “You shall be as God” (Genesis 3:5). Sadly, those who buy into the Word of Faith movement are still listening to him. Our hope is in the Lord, not in our own words, not even in our own faith (Psalm 33:20-22). Our faith comes from God in the first place (Ephesians 2:8; Hebrews 12:2) and is not something we create for ourselves. So, be wary of the Word of Faith movement and any church that aligns itself with Word of Faith teachings.

Bottomline: The theology of Positive Confession, in all its forms, are at the least heterodox and at worse heretical in its teachings. The theology is not biblical in any respect.