I have post you a detailed replay but seems to be that my massage is now here..
Any why... i suggest you to unlock your blackberry in order to use it in other countries with a pre-paid sim cards...

I also have a blackberry (T-Mobile) that i use outside the US.

Just make sure you have the option to insert a sim card to your cell phone.

In this way you will save a lot of money because it's cheap to unlock your phone instead of renting other blackberry outside the US.