Apple Music could become the tech giant's new billion-dollar business

Apple Music now has 15 million subscribers, Cook announced at a Wall Street Journal technology conference in Laguna Beach, California, on Monday evening. Of those 15 million, 6.5 million are paying customers (the other 8.5 million are still on Apple's free three-month trial). Subscribers pay Apple $10 a month for access to unlimited streaming music.

Do the math: 6.5 million times $10 a month times 12 months in a year = $780 million.

That's not quite a billion, but Apple only needs to convert 1.8 million more of the free-trial subscribers to reach that mark.

And Apple Music, which la