Until recently I had never heard the term Oneness and I attend a church that believes in Oneness!! lol
I'm interested to see a debate where people are not questioning God's existence but getting involved in searching out His word!

So, if you (like me) never heard Oneness or maybe you never heard of the Trinity here are the basic differences and similarities between the two theologies.
taken from http://www.onenesspentecostal.com/onetrindisagree.htmOneness believers and Trinitarians (1) both believe in one God; (2) both believe the Father, Son, and Spirit are God; (3) both confess that the Scripture makes a distinction between Father, Son, and Spirit; (4) both believe the Son of God died on the cross, and not the Father; both believe Jesus was praying to the Father, and not to Himself.
Oneness adherents and Trinitarians differ in that (1).Trinitarians believe the one God consists of three eternal persons, while Oneness adherents believe the one God is only one person; (2) Trinitarians believe the second person of the Trinity became incarnate, while Oneness adherents believe YHWH, the lone person of the Godhead, became incarnate; (3) Trinitarians believe the Son is an eternal person in the Godhead, while Oneness adherents believe the Son is a term referring to YHWH's human existence; (4) Trinitarians understand the Biblical distinction between Father and Son to be a distinction between two divine persons, while Oneness adherents understand the Father-Son distinction to be a distinction between the way God exists in Himself (Father), and the way He has come to exist as man (Son).
Where Trinitarians and Oneness adherents differ is not in the fact that one confesses the full deity of Christ whereas the other does not, but who they understand the divine person of Christ to be: the second of three eternal persons in the Godhead, or the one uni-personal God Himself. Neither questions the full, eternal deity of Christ, but differ on their understanding of that divine person's identity. Oneness theology understands YHWH to be uni-personal in nature. That solitary person Himself became man, not the second person of a tri-personal God. The deity of Christ is known as YHWH before the incarnation, and "Son" only after the incarnation, to distinguish God's new existence as a human being from His continued existence as man. "Father" and "Son" are appellations used to describe the relationship between God's two modes of existence. Trinitarian theology, on the other hand, identifies the deity of the Son as "God the Son," the second person of a tri-personal God who became incarnate. "Father" and "Son" are indicative of two distinct divine persons.
The two theological camps also define "Son" quite differently. Trinitarians understand the term to refer to both a pre-incarnate eternal person, and that same person made flesh in Christ. Oneness adherents understand the term to be applicable to God only after the incarnation. God became Son in the incarnation. "Son" is a relational term that surfaced only after the incarnation to describe God's human existence, and distinguish that mode of His existence from His continued existence as God transcendent. "Son" never refers to the incorporeal Spirit alone apart from referencing the humanity of Christ. Oneness adherents are opposed to the term "God the Son," because it equates the word "Son" with deity alone, for which there is no Biblical support. "Son" alludes to and emphasizes the humanity of Christ, but by no means does "Son" refer only to Christ's human nature. Only the whole person of Christ-both deity and humanity-can rightly be called the Son.2
(although this was written from a believer of Oneness, I felt it gave the most thorough yet simple explanation of the two theologies)