eWhisper - 1:05 pm on Mar 18, 2013 (gmt 0)
If you apply a bid modifier of -100% mobile; the campaign will not show on mobile devices.
If you have mobile pages, then you can create a regular desktop ad and a 'mobile preferred'ad so each ad goes to the correct page by device.
Use the desktop destination URL in the typical ad and the mobile destination URL in the mobile preferred ad.
The URLs by ad preference will let you control if the user sees your normal or mobile page, and if you just want to skip mobile for now; -100% mobile bid adjustments will keep you off the device completely.