What it Means to be a Christian
The following is a very short description of the essentials of Christianity and should not be construed as the whole story. The whole story is so magnificent that the following text cannot do it justice.
1. Mankind is in a state of open rebellion against its Creator (this is called "sin") and all people have incurred the death penalty as a result.
2. God, the Creator, nonetheless loves humans and has provided a means of escaping the death penalty. This means is the sacrificial death of His only begotten Son, Jesus Christ.
3. God, the Father, raised Jesus from the dead and elevated Him to the position of Lord over all.
4. All who believe (trust) in Jesus and His sacrificial love become adopted children of God, are forgiven all their sins, are changed into new persons, and get to live forever with the most wonderful Person in the universe. This belief is not simply intellectual ascent to God's existence, but it is an act of faith to leave everything behind in order to be completely comitted to Him. Real Christianity is a relationship, not a religion. You cannot be a Christian unless you are willing to be 100% committed to Him, giving up your own ambitions and desires in exchange for His.
Note that all of this is clearly taught in the Bible. If you don't have a Bible, get one (we recommend the New International Version, but most modern translations are good). If you have a Bible, read it. Get to know more about the One who died for us, and then get into intimate relationship with Him. Connect up with a church (one which preaches Jesus, not religion), and join a family of millions across the world.