Using Blackberry in Hague...

Hello,

I'm just wondering how phone plans in Holland work--I have a Blackberry Bold with ATT as my service provider and I'd like to use this phone when I move to the Hague (though I will have disabled ATT at this point). Is there a prepaid sim card in Holland that will work on my phone? Does this include internet/BBM?

Is there a place in Holland where I can unlock my phone? (I hear it has to be "unlocked" before it can be used overseas).

Thank you!