When you add an IMAP-based email account (including MobileMe and Gmail) to iPhone OS 4 (iPhone 4.0), in addition to the previous options you now get a toggle for “Sync Notes”.

Notes syncing was famously listed as an iPhone 1.0 feature but then mysteriously vanished only to return in iPhone 3.0 as an iTunes-limited option (i.e., not push or over-the-air).

Apple’s desktop Mail client includes special folders that serve as repositories for notes, so perhaps this is now (finally) being echoed on the iPhone.

Whether or not this gets tied in to the actual Notes app remains unknown (it doesn’t seem to right now, but it may just not be working yet). It also doesn’t seem to be an option for Exchange accounts (yet?).

If you discover anything else about iPhone 4 Notes sync, let us know!

[Thanks anon for the tip!]

When Steve Jobs first showed off the iPhone at Macworld 2007, and told the world that it would sync data via iTunes, Notes Sync was one of the items listed on his Keynote slide. Meanwhile, over on the Mac side, Apple shipped OS X 10.5 Leopard, and the desktop Mail app popped up a warning about syncing Notes to the iPhone.

This probably led you — as it did us — to believe the original iPhone on OS 1.x would sync notes.

Ha! As if! When iPhone 1.0 arrived in June 2007, Note Sync was MIA, as it was when iPhone 3G dropped in July 2008. Fast forward to iPhone 3.0 Preview in March 2009, however, and — finally — Notes Sync is in the house.

Note: It’s our understanding Notes Sync currently only works with Apple’s Mail.app Notes under OS X Leopard. It would be all kinds of awesome if Apple expanded this not only to Windows Outlook, but to Exchange ActiveSync and MobileMe for a more robust, cloud-based solution. Right?

That, and Tasks and Task Sync. Ahem.