Our boat has an ocillating fan (which can be locked in a fixed position if desired) that blows on the forward pilothouse windows. This in essence accomplishes what RTF says with regards to increasing ventilation. I've seen boats with a pair of these, one in each forward corner of the pilothouse.
I suppose you could install double-pane windows in the pilothouse, but they would need to be made of laminated safety glass to preven them from shattering if struck by a person, wave, etc. Wouldn't be inexpensive to have windows made for this, however, and their additional thickness may pose mounting or operational problems.
You could try a dehumidifier, but I'm assuming something that would do the job properly might have to be powered, so you'd need to have a sufficient power source for it.
If your boat has a proper heating system--- diesel or propane furnace-type--- then running it through the night will go a long ways toward preventing the condensation buildup on the windows as RTF points out with regards to raising the inside temperature.
I'm not a huge fan of leaving these sorts of things on when we're sleeping, particularly a propane-fired system. However, turning the heater on in the morning should get the temperature up pretty quick and so deal with the condensation on the windows. (On our boat it's a moot point since it doesn't have a built-in heating system of any kind, having spent it's whole life in California before we bought it).
Also, while not nearly as effective as ventilation or heating, if your boat has curtains that can be pulled over the windows, this can help cut down the condensation build-up on the inside of the glass by insulating it--- sort of--- from the moist air inside the boat.
