Joss Whedon's Agents Of S.H.I.E.L.D., based on the Marvel Comics organization S.H.I.E.L.D., will premiere on ABC in September, and the first trailer was just released. While there are connections to the Avengers, Whedon & Co. have made it clear in the past that this world stands on its own—“There are characters in it who clearly come from Avengers. So it’s part of the world, but we’re going to be very, very careful that we don’t tread on the toes of the features and build a whole new world. [Whedon's] built a world for us.”
The show will take place in a time after the Battle of New York (seen in The Avengers), which you'll hear mention of in the trailer... which mostly makes us think that it would be cool to have secret superheroes all over New York.
The show will have a Tuesday at 8 p.m. timeslot, and it has tested very well, with much credit to Whedon, who "knows how to create great television with great relationships at the heart of it."