February 08, 2013, 2:41 PM — Here's how you can listen to iPhone music while stuck on hold during phone calls.
1. After the call starts, tap the Home button.
2. Open the Music app.
3. Find the album or song you want to hear, then press Play.
4. Tap the green title bar to go back to your call.
For more, see the original article at the link below.