Has anyone heard of this kind of option? To get maps on a Micro SD Card you could slip into the BB.
The advantage would be if you are doing international roaming (eg. Canadian in the USA) you wouldn't be a target for those exorbitant download charges outside of your domestic data plan.
That was discussed a couple of months back in this forum. Look a little further back and you'll find them. There was one app that a couple of guys were looking at. The problem, of course, is that the maps are far too large for any SD Card, so you can only load a subset for your planned route.
There are two applications of which I am aware which allow downloadable maps... they work, however clumsily, but they will serve your purpose. Their maps are not too greatly large for today's SD Media Cards. Mobile GMaps