Just added new music to iTunes? Use this tutorial to put a "Sync Now" button on your home screen so you can bring over that new music in one touch.
Step one is to select "Menu->Add" from the home screen.
Step two is to select "Shortcuts" as the type of object to add to the home screen.
Step three is to select the "Sync Now" shortcut and place it on the home screen.
Step four is to press the "Sync Now" button whenever you want to launch a sync!