Ok this might be a dumb qustion, but I just got a new Iphone and it was unlocked I did the update( which was stupid and I didn't know) and now the phone says No SIM card installed insert an unlocked and valid SIM to activate iPhone, What do I do now for it to work with my T-mobile service? Thanks

Nothing, we are currently awaiting a fix from the iPhone guru's

Grab a chair and a bag of popcorn, this may take awhile.
Be patient because they are working hard at getting us back online.

So, i'm screwed and the phone won't work any more till someone figures it out? So does this means its bricked or locked or??

you can downgrade but the phone part still wont work but you can use the ipod part and wifi

search this forum for downgrade to find a guide

So since my sister has Cingular service she can use my phone correct? and I can use hers and just get it unlocked?? and it would be a win win situation? or this phone won't work at all now, even with a cingular sim...