Garage Band is an excellent tool for this.
You can import songs, change the key and even slow them down. Even better, you can write your own chords in musical notation and create your own backing tracks, even play them in loops. There's a learning curve but apple ilife has excellent on line help and it's pretty intuitive. Good luck with it. Feel free to reply with questions. JB.
"Just added the Taylor K22e to my collection. Physically, it is the most beautiful guitar that I have ever seen. The lovely KOA and maple combinations are literally breathtaking. The KOA and boxwood ocean vine inlay on the fret board is striking, as…"