sorry I'm going to have to be brutal about iGigBook, it's not a good piece of software. It's not intuitive to use, it freezes a lot on my iPad, and trying to do simple things with it is a pain.
iRealPro is way better, its easy to use, it's stable, it easy to read, and you go onto their website and can click on any of the songs people have uploaded and it'll prompt you to load them automatically into the playlist on your iPad. The only drawback is that you can't import arbitrary files like PDFs.