We've all wondered exactly why Obi-Wan Kenobi is also known as Ben Kenobi. Whether it was a name he originally had, or if he took it later to better hide himself from the Empire. If the following Spy Report is true, then we'll learn the origins of the 'Ben' name in Episode III. And it appears many of us were right that they might change a Younglings name when they're brought into the Jedi Order. To distance them further from any family ties that they had from their old life. Obviously Anakin's name wasn't changed, because he was already beyond the youngling years when he first joined the Jedi Order. Here's the Spoiler Report from TheForce.net.
MTFBWY and HH!!There's a minor quabble among fans on how Obi-Wan gets his name changed to "Ben" in the classic Episode IV. For long lengths to time, fans have speculated that it may be answered in Episode III. Well, from what we hear it will be. Here's how it goes:
Obi-Wan's given name is Ben - but he's been called Obi-Wan for so long no one seems to know otherwise. As they zip around the galaxy in the new Jedi Star/Tiefighters there is a scene where Anakin, having discovered Kenobi's actual name recently (though not seen in the film), calls him "Ben" as a jest in the middle of a blazing firefight. Obi-Wan responds, saying "This is no time for jokes Anakin! Besides you know I hate it when you call me that" - but Anakin persists. "Did Qui-Gon ever know your real name?" he asks. Obi-Wan blasts a few enemy ships, then says he fears that everyone will know now that Anakin does.
Speculation then would lead us to believe that after the fall of Anakin to the Dark Side. Obi-Wan escapes into hiding, calling himself Ben and burying himself on a planet where Vader would least want to return to. He uses the name as a painful reminder of his relationship with the fallen padawan, who he would someday face again one day.
Jar Jar Binks