Here's some references to Jesus and the Trinity:
O People of the Book, do not exceed the bounds in your religion or say things about God save the truth. The Messiah, Jesus, son of Mary, is only a messenger of God, and his word that he conveyed to Mary, and a spirit from Him. So believe in God and his messengers and say not "Three." Stop. It is better for you. God is only one God. It is far removed from His majesty that He should have a son. (Qur'an 4:171)These verses certainly make us think about our monotheistic claims.
O people of the Book, let us come to a common word between us and you, that we worship non but God, and that we associate nothing with Him, and that none of us take others for lords apart from God. (Qur'an 3:64)
What I really found interesting are these verses that seem to open interpretation for a radical inclusivism in Islam:
"If God has so willed, He would have created you one community, but [He has not so] that He may test you in what He has given you; so compete wiht one another in good works. To God you shall all return and He will tell you the truth aobut that which you have been disputing." (Qur'an 5:48)