Currently Being ModeratedNov 2, 2012 7:42 AM (in response to GladysGH)
You probably can't. The mail application does not know that you already read the mail on your iPhone since that information is only stored locally. Likewise, mail does not know, when it downloads a new email from your account, that it has already been read.
BTW, MS Outlook behaves the same way and so does the Android email client for GMail and others.
Currently Being ModeratedNov 13, 2012 6:43 PM (in response to marcetcamille)
If it's iCloud related try a new post in that forum...they know better then most of us.