newbie and need help with nokia 6680

[GCman]

Hi everybody, I bought this Nokia 6680 recently from UK when I was studying there. Ofcourse when I got back home, and tried with new sim card, new network, the phone refused it. Could somebody help me out please, my phone information as below,

Nokia 6680

from 3G

serial number is : <REMOVED>

I very appreciate your help guys, THANKS

[GCman]

Thanks for letting me know subway, I did search under 6680, but nothing. If I left it unlocked , then I will never get to use it! :(

So, do I have to take it back? isn't there a clue?

Thanks for any idea