singing... Karoake

[notanidea]

I am novice to all this so forgive if I dont make any sense. I have posted this in the culture vultures section as well.

DD sings reasonably well. I just want to know whether u can download a paticular background music for the song and she can sing for family get togethers etc., (One of my friend suggested this but I dont have any clue)

I saw recently that someone connected a iphone to the laptop and mike and started singing with the background music with speaker.Is this possible and what do you think is best and practical.