As far as I know the BB e-mail only works in North America. Additionally, if you are getting the voice/data version, and are planning on travelling, make sure you purchase a North American long distance upgrade for the time you are travelling. It all depends on how much you plan to use it, but in some regions, long distance rates billed to roaming users can be significant. You would be wise to plan ahead. Especially if you plan on using it while you are travelling between provider coverage areas. This same advice is useful when using a cell phone while travelling.
I can't speak for message rates when connected to another provider. You should make sure to ask the dealer. I go to Primetime Communications. They have been good to me. And they are right in your neighborhood. Although they are moving to across from the mall in a short time.