Buddhism is more about spirituality than God. I know plenty of Buddhists who also consider themselves Christian. A person can practice Buddhist meditation and pursue Buddhist Enlightenment without it conflicting with such beliefs.

I think however Buddhist philosophy would encourage someone to be more skeptical about the beliefs they accept about the Universe. While it is not a contradiction to believe in God, the Buddha would certainly encourage one to question the nature of God, and the nature of Religion.

It's worth mentioning that within Yoga, there are many Hindu Yogis who believe in God in the same was that Christians do, yet see Yoga(Meditation) as a practice to become more attuned with God.

It is thought that the Buddha expanded on these Vedic Yogic practices, and in a way, introduces an additional element of encouraging people to be skeptical and questioning of the reality they experience.