Does anyone have a location map by zone for all of the BlackBoxes in the game? Is this like others (e.g. inFamous) where the locations are fixed, or do they change?
While it may not be the answer you have been looking for, per se, you don't really need a map in order to find all black boxes (or any of the other collectibles, for that matter).
When you pause the game with the start button, select "collectibles" and then pick an area on the game's map. The game will show you how many collectibles you've already picked up, but you will also see faint gray pulses on the map marking the approximate locations of anything you've yet to pick up. Using this hint system, finding everything should be a breeze.
The locations on these black boxes appear to be fixed, so finding them is just a matter of using a map/guide to go from location to location.
Here are a couple of links:
Between the 2 sites, you should be able to find all 45 boxes without too much trouble. The G4TV site even includes the coordinates for the boxes, so you can just put them into your map as a waypoint and be led right to them.