This information might be helpful. ( the title says leaks but he offers a solution for condensation )

http://www.askthebuilder.com/skylights-and-skylight-leaks/

the skylight is quite new ( just over a year ) . I was told it is condensation, ( in winter) cos it doesn't drip in summer. How do I rid off this condensation ? Would putting a small ventilation of the side walls of the skylight help reduce this ?