Targus's Mobile Security Lock for iPod doesn't make any sense to me. Basically, this dock-connector iPod-only security cable offers very little in terms of true security and IMO is a waste of $40.
Here's why: the 2-foot-plus cable connects to the iPod via a dock connector mechanism with a built-in three-digit combination lock. While any potential thief wil probably not be able to crack the code within a few minutes, the lock itself would be easy enough to rip off the iPod itself. A little tag on our new lock states, "forced removal of secured lock may cause permanent damage to the iPod." Most thieves won't know this, nor would they care.
At the other end of the connector is a plastic case that retracts the cable; you secure it to yourself (or desk or backpack) by looping the cable through the somewhat bulky case. This cable is so thin that a decent pair of scissors will cut right through it. I can understand the benefit of using it at your desk and keeping it safe from coworkers, but then you can't charge or sync it. On the go, the lock is a bit silly-looking (see photo). If you're worried about getting mugged, stick that thing in your pocket.