the main point is that your phone it's locked if it can read your sim card but another sim card from another operator can't be read.
This means a locked phone.
And for the test point... sorry but i can't help you because i never done that so i don't know tutorials links or something else.
yes, that's what happened to my phone. i had problem with my original phone so cingular replaced one for me. then when i want to unlock it at&t the new cingular could not find IMEI of my current phone. they claimed there is nothing they can do to help me even i'm pretty upset about it. i really want to use my phone to read another sim card. so testpoint is the only thing i can try now.