I've always been told to never reach into a garbage disposal, for obvious reasons, but always seem to drop items in that I don't want to risk ruining the blades with by grinding them. Is there a tool(s) that can be used to efficiently retrieve items from a disposal?
Circuitry can't just turn itself on; the machine is controlled by a switch.
If the switch is not flipped on, the circuit is not complete and the machine will not run.
Our switch is up on the wall, under a cabinet. There is no chance of something hitting that switch accidentally, so I just reach in when something falls down the drain.
If I thought there was even a chance that the disposal could turn on, I would never reach in there.
Whatever you decide to use, unplug the garbage disposal first if possible, or turn off the circuit breaker it is connected to. This makes absolutely sure it can't be accidentally turned on. It is the same principle taught in shop class before changing the blades on the table saw and is well worth the extra few seconds of effort.
Well, definitely don't turn it on while your hand is down there :)
Seriously though, practically speaking, the disposal is physically incapable of turning itself on or causing you damage when it is off. It is turned on by a switch (like a light switch). What happens when you flick the switch is that a circuit is completed -- this is what turns it on. When the circuit is incomplete, electricity cannot travel to the disposal. In theory, a strong enough electric surge could theoretically "arc" and act momentarily as though the switch were on, thus closing the circuit. However, in practice, this would (as Hobodave mentioned) either fry your fuse (causing it to not come on), fry your disposal (causing it to never come on again), or throw your circuit breaker (causing it to not come ever again on until you reset the breaker).
(Any electronics people, please forgive the simplicity of the above. I am intentionally trying only to convey the practical truth and am trying to avoid the full lecture on electronics.)
This is not to say that there couldn't be something dangerous in this dark tight space (like a blade, or broken glass) but this is always a potential concern. If you're careful and slow, there is no danger to reaching in as deep as your hand will allow into a disposal. The first time you do it, you will get the willies when you feel those disposal blades, but be careful and you'll be perfectly safe to do this by hand. If your hand is not small enough to fit into the opening, find someone whose hand is small enough. The space down there is tight and oddly shaped. I have thin hands which have been down there way too many times and I can promise that there is likely no tool which can navigate the weird angles and retrieve your lost item.
Edit: OChef appears to mention such a tool: http://www.ochef.com/products/alligetter.htm