I found G-1 phone in my store, some body left it there and its been a month nobody come to claim this phone. This cell phone is locked i mean I need to sign in the mobile device however i dont know its username and password. I saw some advertise regarding unlocking G1 cellphone however I am still confused, was it possible to unlock this phone even without signing google account.

 Would be very glad to hear good news from you guys

Yes, what kind of service you have? If you have a T-mobile service you can call the T-mobile customer service or have you friend call if they have the service, they will provide you an unlock code in the email. That's the best way you do it.Also, there are various companies they unlock the phone too, But they charge you more  than 20 dollars. Hope this helps.

Damn ure lucky :)

You might wanna Jailbreak aka Root ure gphone as I did with mine (however I had to pay to get mine :( )

http://forum.xda-developers.com/showthread.php?t=442480

Follow the steps and u shud now have access to all and beyond. Good luck. BTW i dunno if ure aware, but there's an app which can send your gps location via sms to whoever has the master passwrd.

U shud install it after rooting so u dun lose ure *new* phone ;)

Enjoy!

I didnt see any option for reseting username and password. While I swich on the phone it comes directly with user id and psswd, and moreover it shows too many attempts too

there comes the option of emergency call and sign in only.

 so in this case is it still possible to use it.

try this code
http://akarsan.blogspot.com/2009/02/how-much-you-are-going-spent-for.html

YOU CAN GET The master reset code from service provider and reset it.....