Multitasking with Player
With most iOS devices able to run multitasking, you can start the Player then switch to another app to read your lyrics etc. Your lyrics can be stored in Notes app or modify charts and view them in Photos.

Ideal for
-music notation (iPad size is good for this)
-guitar tab
-guitar chord diagrams
-practice material
-fingering charts
-add anything to iReal book screenshots
Great for Live gigs!

Here are the steps:
-open your (lyrics) page
-open iReal book
-find song chart
-set up Player settings (audio count in set to off if playing live, volumes of instruments etc.)
-set the count for 2 bars (which gives you time to switch to the other app.)
-press Play
-quickly switch back to your lyrics

I will post information on PDF viewing in another post.