In brief, the physical installation simply involved plugging the AV cables (included) into the SlingBox and our set-top box (a Philips Freeview box, to be precise), then taping a couple of IR emitters onto the front of our set-top box, and finally hooking the SlingBox up to our router (via a couple of SlingLink ethernet wall-plug bridges as our router was too far away).
ENGADGET: App review: SlingPlayer Mobile for Android