Go to PBS.org and click on "TV schedules" tab. Then search out the schedule for your area.

You should be able to find the schedule for after midnight, too, by clicking on the "next" arrow. Even if you've missed it this evening, PBS usually re-runs their specials during the wee hours, at least they do here in Dayton, Ohio. Sometimes, they even run them twice during the early morning, just to fill air time. If so, you can set your VCR to record it while you sleep.

Good luck!

PS: If all else fails, it will probably be available for purchase on CD/VHS. Most of their special are.