Love the forScore app for the iPad. it works great with dropbox for adding pdf's.
Of course you can also add pdf's to the iBook app. This works better because you add annotations. Mail pages with or without annotations. I just added a pdf I made of the book Artful arpeggio's by Don Mock.
I copied the book which I had for years onto the computer added it to a dropbox folder and uploaded it to the forScoreapp on the iPad.