John Wirth, a writer on Terminator: the Sarah Connor Chronicles (T:tSCC), let fall a major revelation for the upcoming second season during the T:tSCC panel at San Diego Comi-Con. (spoilers)

One of the following characters will die during S2: Catherine Weaver, Agent Ellison, Cromartie, Derek Reese, Cameron, Sarah Connor or John Connor. There was immediate speculations among the actors, as well as the audience, as to who will be terminated.

In an interview with TerminatorSite, executive producer, Josh Friedman, mentioned that they have almost completed writing the episode where that death will occur.
However he wouldn't give any hints saying only,

"You could narrow it down a little bit, but why do that?"

He also let drop that something significant will occur in the first few episodes, which will provide them with an "engine" to go on several missions. Eagle eyed spoiler hunters can find out what occurs by looking at the Season 2 previews. Since Cameron goes on a rampage seems a bit obvious, perhaps another trip to youtube is called for.

After all, waiting until the September 8 for Sarah Connor to start up again is far too long a wait.


Sources
http://www.terminatorsite.com/cc08-friedman.htm
http://www.youtube.com/watch?v=trZy9qthjRA&feature=related