I tried to sync music from iTunes to my iPhone and when I click on "on this phone" the songs are there, but they are greyed out and have a circle in front of them. I can not click on those songs and when I eject the phone they are not on the phone.

Delete the full iTunes libary. So not when you connect your iPhone. Just all the music in iTunes. Than, add it back. And now connect your iPhone > and Sync.

You sure got me confused and I'm not having a problem. Perhaps you could explain your answer a little more clearly and with more details. How does one delete their iTunes library off their computer then get it back? Do you really mean that?

I am having the same problem. I have just tried this. Unplug iphone > open itunes > delete all music from itunes library > close itunes > re-open itunes > add music from original folder > plug in iphone > select songs > press sync > unplug iphone using eject button onscreen > checked phone .... still nothing in music folder on phone. On itunes the "On this iphone" tab the songs remain there but greyed out.