Wirelessly posted (iPhone: Mozilla/5.0 (iPhone; U; CPU like Mac OS X; en) AppleWebKit/420.1 (KHTML, like Gecko) Version/3.0 Mobile/4A102 Safari/419.3)
With your iPhone plugged into your computer select it in iTunes. Next select the music tab at the top. Lastly select which playlists you want or you can select to sync all music if it will fit.