If you have played around with Garage Band, but never dug deep into it, you may not know about the musical notation view. It's a view that shows traditional musical notation. You need to add a software or midi instrument to use it. Software instruments are the easiest. I simply like to put a few of the pre-defined music loops together and then play with it there.
Let's get to it:1. Open Garage Band and create a new song. 2. Name the song, tweak it however you like, and click 'Create'. 3. Now, click on the loop browser. It's the one that looks like an eyeball in the lower left of the screen. Click on it, and the loops should pop up. Select a predefined loop and then click and drag it to the timeline at the top.
Be sure that it the loop icon is 'green'. These are the ones that can show the notation.4. You should now see your instrument loop on your timeline. Make sure it's selected by clicking on the instrument icon on the far left of the track. Next, click on the edit button (it's the one on the lower left with the scissors). under the Region column click on the 'musical note'. This should change you to the notation view. From here, you can click on individual notes, to hear them, or click and drag them to move them around on the scales. You can also ADD notes under the ADVANCED Column, Now have some fun with Garage Band!!
Caveats: Apple doesn't permit you to print the scores ... so the only way to do it is with a screen shot and print that.