Syncing Notes with Gmail & iCloud
Your notes can synchronize with Gmail or iCloud, not both as far as I can tell.

To sync a note with Gmail do the following


Set up your account and check the notes box in the Mail, Contacts &amp; Calendars preference pane.
Go to notes in Mountain Lion
Go to View -> Show Folders List -- or -- click the folders list icon in the bottom left side of the Notes window
From here you should be able to select your Gmail account instead of iCloud and create a new note
Within Gmail you should have a folder called "Notes" and your newly created note should be inside