Protector for camera lens window on HTC Desire Z? (protect from scratches)
I can understand your concern, but I've also never seen a film that specifically covers the camera lens window. I haven't used a Zagg, but other screen films I've purchased in the past included the excess film on the card - if the Zagg included this you could possibly cut your own square or circle to cover the lens window. Otherwise I'd suggest checking your retailer of choice for another inexpensive film that you can use to cut your own window from.

In the past I've purchased screen protectors on clearance from places like Staples, Walmart, etc for obsolete devices so I could cut them to protect camera screens, etc.