To answer your question yes, you will need DNS or something to point the users to the DR site.
This is a great opportunity to place VMware on NetApp. With NetApp, SnapMirror and VMware running SRM this can be automated....and it works.
Is this a iSCSI, CIFS, NFS or FC install? Are there servers at the DR site? will you use the WAN for clients to connect to the DR site or is the plan to have the users at the DR site as well?
If you want to use a destination volume that was created for SnapMirror you have to "Quiesce" then "Break" the mirror. When you break the mirror it will mark the volume as read/write. Make sure you are using SnapDrive and/or SnapManager to initiate the snapshot and it will update the SnapMirror. You need to use these products to make sure the data has been quiesced from the applications perspective OR make sure there is no IO when you do your final SnapMirror update.
The customer is running CIFS and NFS, no iSCSI or FCP. The customer is looking into purchasing VMware and will be implementing it in another week or two. SRM will be a product the customer will be buying along with Vmotion and the whole nine yard.
At the DR site, there is no servers nor any users connecting to the DR system. We want to shutdown the primary site and point everything to the DR site and have business continue as normal.
That makes it a lot more simple. When the real outage or DR plan is tested you should update DNS. If you are just doing a demo and you don't want to point all of the users to the DR site I would either use the IP address of the DR site's NetApp or modify you computer's host file to simulate DNS being update.