Since the release of the latest firmware version 1.1.3 iPhone users have had to deal with their SMS messages being displayed out of order. This obviously is a major issue considering how many text messages are sent and received through out the day, but today Apple posted an easy fix to the problem ? simply Choose General > Date & Time and turn Set Automatically to ON.
The website also states "(Note that in some locations, network time may not be available and in some cases, you may not see this option)."
Source: Apple