USING BBM WITH WIFI
The only requirement to be able to use your BBM over Wi-Fi is an active BBM Data plan. If you have an active Blackberry data plan then you are able to use the BBM via Wi-Fi as well as other features on the phone. If you don’t have an active Blackberry data plan the BBM Wi-Fi will not work.
In order to avoid roaming charges make sure that you have your mobile network off. You can learn about using your cell phone overseas by clicking here.
If you want your phone for GPS you can use GPS without any coverage at all. Many times while I was traveling through Sicily and Colombia I was able to use Google maps when my coverage when out. The trick is to make sure you load the maps before you love coverage.
I get this question a lot: Does BBM work on Wi-Fi?? Answer: Yes only if you have an active Blackberry data plan