I have just set up Gmail on my iPhone4 using the Exchange/IMAP method (m.google.com).
Everything works great - the only problem I'm having is that when I send a new mail from my iPhone to myself, I get the new mail notification twice - once for the new mail in the inbox (as expected) but then a 2nd notification chime for the sent item.
I want to keep my Sent Items in sync between my iPhone and Gmail, however, I'd rather not get the Sent Item chime/notification (and have to go in and read it to clear it from my 'unread mails').
What I'm trying to achieve is being notified of the new mail in my inbox, but not getting the additional '1 new item' appear in my sent items - I never want anything in my Sent Items to appear as an 'unread/new mail'. In the same way that if I send a mail to someone else, that mail appears under Sent Items, but not as a new/unread mail. It's that same behaviour for the sent item that I'm trying to achieve. I hope that makes sense.
I also noticed similar behaviour if I send a mail via the Gmail website (again, to myself), my mail.app (Mac OS) will show both the new/unread mail in both my Inbox and Sent Items - same behaviour.
Any ideas how to sort this?