Unfortunately no. Since every operator on this planet who offers BIS uses Blackberry's servers for this service (as opposed to running own infrastructure) you can't use a Blackberry device with another operator unless your original operator has unregistered your device with Blackberry.

Amsterdam and spain
 

Going to amsterdam and I have an Iphone4 and its unlocked. If i want to use a prepaid sim which one do i use to have data which is really what i care about. I have a T-mobile pre-paid sim and a vodafone prepaid sim also how do i go about adding the money into it.

All your information will be greatly appreciated thanks

Vodafone - Top up voucher -Vodafone - Prepaid - English summary
Basicaly you go to any gas station, super market etc and get the vouchers to top up. Same thing for T-mobile.

With Vodafone you can either pay 4,75 euro for 250 MB or 7,25 for 1 GB (both valid for 1 month)

I when I used to have a Blackberry, I SIM swapped between a US and UK SIM. It worked, but my Blackberry was on a BES (not BIS) connection.