No.
It is to much to tell, but is is the Dragonball series after Dragonball and Dragonball z. You can see the Dragonball GT series your self at www.idragonball.com.
Dragonball Z Gt doesn't exist, but Dragonball GT is it's own series...
There isn't one that is part of the official release.
The GT series, if you , mean dragonball, it was the second sequel to dragonball, GT means 'Grand Tour' as the main characters (Goku, Pan and Trunks) go on a few big adventures or grand tours. Good series.
They did, Dragon Ball Z Kai...
well to answer you question its AF which stand for Advanced Future.
Well there is DragonBall Kai which is reasonably new, you could give watching that a go.
At this time, there is no official series after Dragon Ball GT.
Yes. The new series is called Dragonball Zeron and will be realeased 2 years later on October 13 2010.
There is a remake of DBZ called Dragonball Kai there are not coming a new season after dragonball gt :'(
DragonBall GT is meant to be the end of the series, after that they finish, but they did make DragonBall Z Kai from 2009-2011.