The Manichean's were the followers Mani. Mani was a Persian who, about 252AD,  mixed Christianity with Gnosticism and other Persian elements. He states his teaching was from Christ and the Persian Magi. Mani's teaching were as follows:

References:

Archelaus; Acts of Manes 47 ECF 6.179 Archelaus;  Acts of Manes 6,7 Eusebius; E.H. 7: 31 & Archelaus;  Acts of Manes 13 Archelaus;  Acts of Manes 20 Archelaus; Acts of Manes 8

Alexander; Of the Manicheans 24 ECF 6.239 Archelaus; Acts of Manes 11 Archelaus; Acts of Manes 33 & Alexander; Of the Manicheans 21 Alexander; Of the Manicheans 21 Alexander; Of the Manicheans 4

St. Augustine was a Manichean for 8 years before becoming a Christian. After becoming a Christian he taught freewill (See: City of God). It was not until 417 AD, while debating with Pelegius, that he began teaching what modern day Calvinists describe as "total depravity" and the "Bondage of the will." 

It seems that in reaction to Pelegian doctrine that "man could be sinless from birth" Augustine went too far the other way.

Notes from Church history:

• Archelaus 33 – The Judges concluded against Mani that: man has free will, so if Mani can sin his spirit can’t be an emanation of God. And the angels, and Satan (dark evil god) are not of Gods essence.

Other notes from the writings of Augustine (not referenced yet):

• When the sun and moon have liberated all the light they are able, there will be a fire kindled on the earth which will burn for 1468 years, when there will be no light left. The King of Darkness and his hosts will thereupon withdraw into the pit prepared for them. Man, therefore, unlike the world, is the creature of demons, the aim of the demons being to imprison in man, through the propagation of the race, as much as possible of the light, and so to hinder the separating process by the sun and the moon.  
• Common Manicheans celebrate Sunday, the consecrated ones (the `Elect') celebrate on Monday
• Salivation is by rigorous asceticism, and by the practice of certain ceremonial observances
• Manicheans deny the saving efficacy of baptism
• Salvation consists simply in the liberation of the light from the darkness. In the case of the Elect this takes place immediately after death; in the case of adherents who have not practiced the prescribed forms of asceticism, it takes place only after considerable torment. In the case of the ordinary sensual man, there is no deliverance.
• God of the Old Testament as an evil Their objections to the Old Testament Scriptures an religion were in general substantially the same as those made by other Gnostics, especially by the Marcionites

Comments from the translators preface of the Anti-Manichean writings, I have not looked these up yet:

• Augustine in reaction to Mani teaching god is mutable almost goes into fatalism. It would be easy to point out that Augustine here goes to a dangerous extreme, and narrowly escapes fatalism on the one hand, and denial of the true personality of God on the other. 
• Augustine mentions a disgusting ceremony in which human semen was partaken of by the Elect in order to deliver the imprisoned light contained therein (De Haeres. 46), and he calls this ceremony a sort of Eucharist. But his confessed ignorance of the doings of the 'Elect' discredits in some measure this accusation. 
• Later in his writings against the Pelagian error, Augustine maid certain modifications in his own statements, leading him on some occasions to the verge of Manichean error itself  The Gnostic idea of good spirits being in evil matter contributed to Augustine's speculations leading eventually to the doctrines of "total depravity" and "bondage of the will."
•  In his debates; Mani made him question the nature of evil and sin, Pelagius made him question the sin nature farther.

  More to come!!