iMessage - are the messages stored for access ??

[Futuresgreen]

Hi all - a mate of mine is concerned that iMessages are stored somewhere on the cloud and could be accessed. Ive said that I believe they are just stored on your phone, exactly same as sms, but once the user deletes them, they cannot be retrieved. I guess for security, someone or something somewhere still monitors them in the same way as sms, but as for the general person on the street, they should have nothing to worry about if they were having a private conversation for instance - that they maynot want to share with a family member ! ??