Need help to unlock my iphone 3g

Jigaa

hi guys, can anyone please help me to unlock my iphone 3g. i am in a stage where my iphone says; insert a valid sim to activate.
Secondly, please teach me to download the ios firmware on my windows 7 PC. i did download 4.2.1 but redsnow is not able to detect it.

please send me the details on my email ID sriharsha1726@gmail.com

Jigaa

it had ATNT earlier..not sure if its active or deactivated.

iPhoneHacks

Recommend checking out chronicunlocks.com (http://chronicunlocks.com/).