What are the costs, if any of using bbm while in a foreign country? It uses data so I'm guessing we'll be charged for it and that the free browsing won't apply?
Free browsing won't apply nor free BBM, I'd recommend you to put the simcard of the country of origin where you'll be visit as my uncle came down to South Africa from Spain and they charged him R40per minute on local calls
You'll have access to BBM - all the necessay applications are stored on your phone - unless vodacom and mtn get a BIS roaming agreement like other countries have
You would need to have the BB subscription on the foreign sim but you can access BB over WiFi. I switch data off on my BB when I am overseas and synchronise mail over WiFi.