hi i have a iPhone 3G with OS 3.0

i used pwnage 3.0 to jailbreak but unfortunately after the pwnage tool builds a custom ipsw and directs me to DFU mode, itunes says waiting for iPOD.....then comes up with an error msg.

please help
i have tried redsnow as well but that isn;t working either.
on redsnow after it says waiting for DFU mode, on the waiting for iPhone reboot, it just gets stuck on that. i left it for 30/35 mins and it was just saying waiting for reboot.

please help me jailbreak my iPhone !!! please somebody help !!!