If there were no punishment for sin would salvation be necessary? Every time I hear someone say that 'If God were a loving God he would not send people to Hell', It makes me wonder Why does God, who is such a loving God send unbelievers to Hell.

Since Jesus said that the Lake of fire was created for the Devil and his angels, and not for unbelievers;

Matthew 25:41  KJV


  Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels: 


I have heard that there are some Christians who do not believe that God will so punish unbelievers.

Are there any mainstream Churches who endorse this position?
At one time, the belief in universal salvation was the defining characteristic of a Christian denomination known as the "Universalists" or the "Christian Universalists." 

That denomination, however, merged with the Unitarians, and is no longer considered a Christian denomination by people inside or outside that church.  There remain some Christian Universalists, but not with sufficient numbers or organization to be considered a mainstream Christian denomination.