Is there a way to keep my blackberry device from marking mail I read as opened/read. I would either like my blackberry to mark emails as read on the device and my desktop PC or just my desktop PC. Please Help. Thank you.

Turn off Wireless Reconciliation from your handheld.
Messages > Options > Email Reconciliation
choose your Message Service and then set Wireless Reconcile to Off.

Will this stop the wireless sync of my calendar between my device and desktop computer?

No.

thank you for the help. I get a message telling me that all folders will be affected by this action and I wasn't sure because isn't the calendar one of those folders? Also if I decided that I want to change this back will any re-activating or service book re-sending have to take place?

The calendar won't be affected. It has it's own set of sync rules.
Changing back will not require any service books to be sent, or reactivation.