Honestly, I feel a bit apprehensive about contiuning this thread because I don’t want this to turn into a Great Debate, to prove whether Christianity is really true or whether Jesus really exists. And I somehow always get the feeling that Christians are not really welcomed (and aware of the impressions that many church-goers and bible-readers give), so a disclaimer first - I am not saying whatever I say here is the undeniable truth. It’s just what I think it’s the truth.
Christians believe that at the beginning mankind and God are supposed to have a cordial, personal relationship, a friend to friend relationship or something more akin to a parent-children relationship (a good parent-child relationship, I have to add).
To cut the long story short (about the whole of the Old Testament), the relationship was broken, God desired the relationship to be restored and that where Jesus entered the picture. Jesus died on the cross, paid for the mistakes that men has done and hence allow men to once more have a relationship with God through Jesus Christ.
So basicially if a man believes that he has sinned, God exists, Jesus Christ is the Son of God, that Jesus paid for his sins and willing to accept Jesus as his Lord then it’s done.
Though the Bible describes the relationship between Jesus and a Christian as one of a Lord and servant, the Bible also at times protray the relationship as one of friends. I personally believes it is a balance, but this is a sore point for me too (a reason why I stop practising the ‘Christian’ religion for a year or so). Some church-goers would have you believe that Jesus or God is a hard task-master and he would be displeased if you don’t do this or that while some protrays the relationship as where Jesus understands each individual’s problems and weakness.
So to answer the OP, it depends on whether one become a ‘Christian’ by acknowledging that one has been in the wrong, and will always do wrong, that he would never be good enough to meet God’s standard, that he accept God’s forgiveness and that he wants a relationship (as described above). All that he has to do, to quote Augustine, is “love God, and do as you wish” (but “love God” itself has a lot of explanation to be done with it).
And naturally, do love God first one has to acknowledge that He exists.
And no, to be a Christian doesn’t mean you have to bash gays, stop playing RPGs or Dungeons and Dragons, go to Church every week, study philiosphy or other religions. Those are additions by men.
Okay, serious, this beginning to sound like a Four Spiritual Law tract so I sure others would explain it better. So I’ll end here…