When Marcus and his role-playing tech geeks friends ditch school on the wrong day (a terrorist attack hits San Francisco, throwing the city into chaos) they are arrested by homeland security, and mercilessly interrogated for days. The depictions of these teens being tortured is just the beginning, however, and when they are released, it is into a San Francisco where everyone is treated like a potential terrorist. Fast Trak transponders are used to track people's movement, the internet is heavily watched. And so Marcus does what any brave tech nerd would- he starts a rebellion from the computers up.
It's a must read for any kid who witnessed the Bush administration, which is to say, I really do think all teens should read this. It was already named NYT top 10 books for YA in 2008, and is up for the Nebula as well. But awards aside, what really amazed me about this book was the way it textured my life after I read it. Doctorow lifts the veil of technological surveillance such that even the most tech-lame citizen (like me) can see it for what it really is. Like MT Anderson's Feed, which is also a must-read, it is impossible to return to your normal tech-consumer lifestyle after the last page is turned. What is extra cool about Little Brother is that rather than making you want to live off the grid in some cabin in the woods where no one can find you ever again, it inspires you to take a hold of the technology available to us and figure out how to use it with as much autonomy as you can muster.
You can also check out this super cool blog, to which Doctorow contributes: http://boingboing.net/