This question is starting to come up more and more as people continue to buy more bulk ammo. Here is the answer to the difference between boxer and berdan primers.
Berdan primers have the anvil located in the center of the primer pocket and have either 2 or 3 peripherally located flash holes in the primer pocket.
A Boxer primer has the anvil located within the primer cup. The brass has a central flash hole inside of its primer pocket through which the flame from the primer travels.
A Berdan primer does not have an anvil located in the primer cup. The anvil that the pellet is crushed against is located inside cartridge's primer pocket with flash holes on either side to allow the flame to propogate through.
Both types of cartridges (berdan and boxer primed) are reloadable and you can purchase primers for either. The Berdan is, for obvious geometric reasons, more difficult to reload on a standard press. However, there is no reason that they cannot be reloaded if you so choose.
Here is a comparison of the primers:
Note: the type of primer is not always indicative of corrosive or non-corrosive powders.