Its about people who are Heroes!
Haha, it focuses on a group of people that are unaware that they have a special power such as healing oneself, time travelling, etc. There are some outside forces(people) who are aware of people and have their own plans for them. I don't want to get too descriptive as there are other sites that will do a better job.
It was much better than I expected. I did not watch when it came out, I ended up purchasing it via iTunes. It was defintely worth it given the length of the series. May I recommend that it would probably be better in HD DVD if that is an option for you.
1 spoiler from the summaries you might find:
HRG = Horn rimmed Glasses