Go to apple website for apple id or password recover.
.. Recover Your Apple ID
site enter your name surname and email id which you have used for apple id registration. Then click on continue this will recover your apple id.
Even searching your old email form apple also help your to find your appple id.
Once you get your apple id you can reset your passcode by below method.
You dont need security question, apple will ask for security question and you just need to answer them. I guess you forgot your apple passcode. try to reset passcode by following method
Again go to above website and enter your apple id. and then continue.
It will ask for
Select what information you want to reset.
I need to reset my password
I need to reset my security questions .
Select i need to reset my password and click continue.
then you will get following dialog box.
you will get email for passcode reset. try this i hope you can reset your lost passcode.
Here is other way to unlock your ipod iphone if you have fogot your screen lock or patten lock passcode