I have unlocked my Treo 600, thanks to your help.

But, I still see the mMode when the screen is on the phone mode. When I attempt to connect to use the phone, using another GSM SIM Card (T-Mobile for example), it asks me to if I want to connect to mMode? If I say no, the phone will not work/dial out. If I say Yes, it works just fine.

Does anyone know how to remove this mMode question from my Treo 600, and not cause any problems?

Thank you to all for your advice!