2. The Game Model
When you are happy with your model, and it has been approved, export the low resolution version and take it into Maya, or an equivelant package.
This will give you a good, low poly base to work up into your game model, so its now time to chop out all the extra polygons you don`t actually need. These will include geometry added to give detail which the normal map will cover, so are now redundant.
You can also use this time to optimize the model, removing any polygons which don`t actually add to the models silhouette or topology.
NOTE: Its generally easier to work on half the model at this stage, so long as your model is symetrical.