Two of the best high school chemistry classroom/lecture style video series are:
AP Chemistry Video Essentials by Mr. Anderson of Bozeman Science on YouTube
IsaacsTeach also goes through a high school level chemistry lecture series.
A popular science chemistry series for everyone, not just high school students:
Chemistry by Crash Course playlist at YouTube
Some other online chemistry video series you might want to check:
Some of the Chemistry Now videos are also available at the Science360 video library, as well as many others.
eCHEM 1A Modules at UC Berkeley College of Chemistry (newer)
The Chem Doctor has gobs of videos on many chemistry topics.
Periodic Table of Videos at YouTube go through the elements, one video at a time.
Chemistry Behind the Magic: Chemical Demonstrations for the Classroom is a series of lectures that show and explain some spectacular chemistry demonstrations.
Khan Academy has a chemistry section. It is not as thorough or engaging as some of their other topics. The math videos are awesome.