What do you do when you come to a door jam? Jams usually go down nearly to the subfloor. You have two options. One is ugly, at best, and the other is tedious. You could try to cut around the jam and try to make a fairly tight fit. You probably won't succeed though. You actually need to leave a little gap around the jam to allow for expansion of the wood. This gap also allows for looking ugly and for debris to fall into the crack. The other option (preferred) is to lay a scrap piece of laminate flat, near the jam. Then take a cutoff saw and, using the laminate as a guide for the proper height, rest the saw on the scrap piece and trim off the bottom of the jam.

Take a look at the illustration. This allows you to cut the jam straight, and gives you a heavy 1/16 of an inch between the jam and the laminate (depending on saw kerf). That allows the laminate to move freely under the jam. When you actually put your piece under there, make sure it is still about 1/4 of an inch away from the actual wall that is behind the jam. This way, as the floor expands and contracts, it will always appear the same, no gap between the jam and the flooring.