Lordship salvation is basically when you submit yourself to Christ, obeying him, turning from sin, and receiving him as your Lord. The premise: that Jesus cannot be one's Savior without also being his Lord.
This is a theological dispute, sometimes called the "Lordship salvation controversy", or "Lordship Controversy". One site that takes this from two views with John F. MacArthur Jr. on one side, and Charles C. Ryrie on the other, says:
The issue as seen by those who believe in lordship salvation (e.g., MacArthur) is that someone who is truly saved will produce fruit that will attest to the genuineness of his faith, because he will have acknowledged Jesus not only as his Savior, but as his Lord as well.
Those who reject lordship salvation (e.g., Ryrie), believe that someone may have genuine faith in Christ, but the fact that he continues in his sin demonstrates that he has not made Jesus his Lord, only his Savior. According to Ryrie, just because someone sins or acts in disobedience (even habitually) doesn't mean he doesn't have saving faith.
I am not really sure if this is the position of any Major Churches; I would guess that it is more individual belief.