I have an e-mail client set up to receive all my Gmail e-mail but without deleting it because quite often I'm not at home and still want to be able to read my mail. I just wondered if there is a way I can mark the mail that I read in my client as "Read" in Gmail, the webmail application.
If you set up your mail client to use IMAP instead of POP access, all those things will happen automatically for you. eg Read status, deletes, folder moves etc will all be replicated back to Gmail.
Here's how to set it up: http://mail.google.com/support/bin/answer.py?answer=78799