Yes, indeed the DVDs are now available on a first-come, first serve basis.
The NSTA has a link to the DVD giveaway page. And the NABT (National Association of Biology Teachers) has written about it, too.
From the NABT:
The DVD's will be given away starting Monday, December 18, 2006 thru Thursday, January 18, 2007. Teachers are encouraged to log on to www.participate.net to request the DVD, which will be delivered within 6-8 weeks. Every teacher must provide a nine-digit federal tax ID number belonging to the school where they teach.
A free downloadable curriculum guide to accompany An Inconvenient Truth is available for download at Participate.net courtesy of the film's financier, Participant Productions. Developed by Topics Education for Participant Productions and Paramount Home Entertainment, the "AIT in the Classroom" curriculum is aligned with national curriculum standards and is designed for use in high school Earth Science, Environmental Science, Physics, and Chemistry classes. It can also be used in civics classes, middle school science classes, and offers Serving Learning opportunities for students.