Well,Bab2010, I am sorry to say...I don't know if this is done by Apple deliberately or is it a flaw in the iphone but there is a default passcode because scimanc is not the only person who experienced that. I did too and please search the web, many ppl is asking the same question too, so I do believe there is one, and for mine, luckily, it's 1234! I've tried 0000 but lost a chance so I searched around without finding an answer on the internet which is very strange! I called Apple and they asked me to restore my phone to factory setting via itunes but it wasn't successful! So I tried again with 1234 and it works! I am 100% for sure that I have never set up any passcode on my phone so...if it is not default, what else can it be?