This will show you how to sync your notes from mail.app with gmail.
[doing this will let you use gmail to sync the notes.app on your iphone / ipad with your mail.app on your mac]
1) setup a google account in mail.app.
2) any notes you enter will now appear in google gmail’s notes label :D
its that easy!
you can then sync your google notes with your iphone / ipad and any changes you make in your mail.app or in your iphone / ipad notes will all be synced through gmail :D