Thats not true.... im Christian and PLENTY of my friends and all my family are, and we have tattoos. u should see some of the Christian metal bands i used to see when i was younger! Completely covered in tattoos. Dont confused "religious" fanatics with normal people who believe in Christ, God, Allah etc. The Qu'ran says something similar, but you will meet many muslims (especially black ones) who are well tatooed (God bless them looking hot with the tats and beards). There were passages in the old testament that spoke against making the body, usually referring to slave branding or baal worship, not adornment/decoration. I just started number 8.....
This article covers some good points in my opinion: http://christianity.about.com/od/faqhelpdesk/f/tattoochristian.htm. I'm a Christian and I have tattoos, some of which are only covered when it gets very cold and I'm wear long sleeves and tights (or pants). I've been a leader in my church as well as a participant in many organizations where one wouldn't usually think you'd see tattoo sleeves, etc. I don't think God's as concerned with them as much as people are but if I was somewhere and felt that they would have a negative impact on what I was trying to accomplish, I would more than likely put on some sleeves.