Reverse Cell Phone Lookup apps

NumLookup - World's Best Reverse Phone Lookup Tool

NumLookup can help you perform a reverse phone number search and lookup a phone number to identify the owner. You can quickly answer questions like: “Who called me?”, 
“Is this a cell phone number?”
, “Whose phone number is this?”. No registration or sign up is needed to use NumLookup. It is an entirely hassle-free reverse phone lookup tool - enter phone number and get owner's full name.