I recently noticed all my music was gone on my iphone 3gs. Maybe due to the itunes update or some sync mistake on my end. I went to add some music to my iphone by dragging and dropping it into the iphone device like I always did. But now itunes won't allow me. Is this normal?
Check your iPhone's settings to make sure nothing has changed. Connect your phone and click on it's icon in the iTunes source list (the narrow pane on the left). This will bring up the preferences tabs in the main pane on the right. The first tab you'll see is Summary, look for "manually manage songs and videos", if you want to manually drag and drop content to the phone make sure there is a check mark there, if not the setting has changed to auto-sync.