According to ComicsContinuum.com, Jim Kriegg story editor on the upcoming CG Green Lantern animated series, the show will focus on Hal Jordan, Kilowog and a Red Lantern. It will not be in continuity with the movie franchise.
There really aren't too many Red Lanterns in the comics and by far the best known is Atrocitus. So, unless they create a new character for the series, or go with enraged housecat Dex-Starr instead, my money is on the atrocious one. I am definitely interested to hear more about this series coming next year.