I believe you're thinking of one of the later books in that series, Shipgade (Xenocide, I think). Ender's Game is the first book of that series.
After finishing Ender's Game, all these people kept telling me to read Ender's Shadow cause it was so much better. And I'm thinking, ~~~, somehow I doubt it gets any better than this first one.
I believe there was also a couple failed attempts at making a movie for Ender's Game, right?
I've read it and Ender's Shadow at least 10 times each.
Orson Scott Card has been trying for a while to make an Ender's Game movie, with the last script being a 3-hour combination of Ender's Game and Ender's Shadow. That script ended up being scrapped a year or two ago, and I haven't heard anything about the project since.