When you set up your account on the iPhone it brings in 50 of last emails on your account. I've already read them on my computer so i don't want to go through all of them on the iPhone is there a way to get select all of them and mark them as read?
what email service do you have. also, if you have imap it is connected to your computer and email service...
For example i have Gmail IMAP. It sounds like you are on POP.
I use the mail.app on my macbook and if i receive an email to my phone, i view it, it will mark it as read on my phone, macbook, and gmail.com.
With POP service, i do not believe they are connected through the server. Good luck.