The mammoth TNT press release (which I read at AICN) describes the series thusly: "The series opens shortly after aliens have wiped out most of the human population. The aliens are now rounding up the few people left, but they are met with strong resistance from a group of soldiers and civilians who fight for their survival all while struggling to maintain their humanity." Shades of War of the Worlds, pieces of V, maybe a little Battlestar Galactica...certainly not the most original science fiction concept out there, but it's definitely a premise that could support an ongoing series if the writing is up to snuff.
The pilot was written by Robert Rodat (Saving Private Ryan) and the series stars Noah Wyle as "The Reluctant Leader," Moon Bloodgood as "The Unrealistically Attractive Therapist," Jessy Schram as "The Unrealistically Attractive Motorcycle Scout" and Seychelle Gabriel as "The Orphan, Whom We Can Presume Has a Heart of Gold."
Spielberg's TV ventures have varied in the past, ranging from "Oh My God, What An Achievement!" (Band of Brothers), to "Really? This Is Something You Had Faith In?" (The United States of Tara, On the Lot) to "Okay, Steve, You've Had the Rights For Several Decades Now, Can You Please Get it Made?" (Stephen King's The Talisman).
Snark and kidding aside, I'm completely game for a new alien invasion series after the failure that was the new V. Similarly to Push hitting the small screen, television may be the ideal place to examine the concept of an alien invasion in a way we haven't seen before. Not to mention, I need something new to watch when Lost ends this year.