If you have removed the stem entirely, then the forks should just slip out. If they do NOT slip out, there is likely a rubber washer that has been wedged into the top of your headset that is trapping the fork in place. This is a real pain to deal with actually... I recommend using a rubber mallet or a hammer with a block of wood and then hammer your fork downward. You only need to move it about 1/10th of an inch or so. Just enough so the rubber washer is pushed upwards a tiny bit on the fork.
Now push your fork back into place and the rubber washer should slip off and your forks will come right out with no problem.
Really though, nothing 'permanent' holds your forks in place and your forks SHOULD slide off after the stem is removed. That rubber washer, in my opinion, was designed very poorly and is just a major pain.