I live on my trainer all winter (Wisconsin) but couldn't do it effectively without a series of training DVD's to guide me and make it more interesting (ie. Spinervals, CTS training videos and Sufferfest videos). My best winter structured program is the CTS Progressive Power 8 week course. I have raised my 8 min power output by 10-15% in the winter with this series. I then supplement it with longer aero-base workouts, rest days, etc.. These training videos are well worth the money for me.

http://trainright.com/media-2/progressive-power-dvds/