This could be extremely useful or completely useless depending on your phone situation at home. Losing the cell phone in between the sofa cushions is definitely not a new situation for us. How do we find it? Pick up the land line phone and call it. But what if you don't have a landline and your cellphone is also the landline?
You either tear your house apart looking for it, or if you have an internet connection you use wheresmycellphone.com. Type in your number and wait for your phone to ring. We tried it out and it works just fine. You can even add it to your iGoogle page if you are a chronic phone misplacer.
-via The Gadget Blog