Currently Being ModeratedFeb 12, 2013 6:44 PM (in response to T Luu)
If your iPhone is powered on, connected to internet, and the find my iPhone app was enabled previously, you can use Find my iPhone.... as long as no-one else has reset the iPhone to defaults.
Otherwise, you can use your Mac to google a map of the places you have previously been to and then go there to see if thats where you left it.
Currently Being ModeratedFeb 12, 2013 6:45 PM (in response to T Luu)
Assuming that you enabled Find My iPhone on the phone before it was lost, you can use that:
If you didn't enable that, or any other similar thing, there won't be any finding it this way.