Create+a+No-Reply+email

Exchange 2003
There are a couple of ways to limit incoming mail in MS Exchange 2003. The easiest one is to change the permissions on the no-reply account using the Active Directory Users and Computers MMC. In the left pane expand the entry for your mail domain. Click Users. In the right pane double click the no-reply account to view the properties dialog. Click the Exchange General tab; then click the Delivery Restrictions button. You can set the maximum receiving message size to zero (or whatever). You can set the account to receive messages from authenticated users only or from a specific list of users.

Another method is to make a rule to automatically delete all messages sent to the no-reply account.

The reply to feature is in the Outlook client message options. I'm using Outlook 2007 so I can't be more specific, but I believe it is used on a message by message basis.