The Private Life of Plants (1995) is a BBC documentary written and narrated by David Attenborough. The six (50 minute) episodes of this Emmy Award winning documentary are available FREE to watch on Google Video.
Any teacher of life science concepts will find all or parts of these videos to be suitable as a supplement to instruction. Holds up pretty well after 15 years.
See Episode 1-Travelling- embedded below.
Science for All 