Which carrier?? I think it is either Cingular or T-mobile from your description. I think the phone is asking for either the default pin code (in your manual, unless you changed it) or the PUK code (only available from your carrier by calling customer service). Hope that helps.
Please help me...I reinsert my sim card into my c56 phone, now when I turn it on is asking for a phonecode..i'm lost help me