Ontological arguments are based on the concept of God as proof of existence; teleological arguments provide proof that God exists; and cosmological arguments are based on a cause to prove God exists.
The ontological argument attempts to prove the existence of God through reasoning alone. It states that since God can be conceived it means that God must exist. It is not based on observation of the world nor on evidence derived from it. It is not a cause and effect argument and thus unlike the cosmological and teleological arguments.
The teleological argument states that the world is so ordered intricately and purposefully designed that there must be a creator. In other words the world shows the effect of complexity or design; thus it must have been designed by a great Designer or God.
The cosmological argument states that everything we see has been caused by something else which keeps it in existence. In other words the world could not just exist on its own – something must have made it and that cause is God.
For greater understanding please refer to:http://pegasus.cc.ucf.edu/~stanlick/complgodoutline.html