I'll be pitching my novel to agents at the South Carolina Writers Workshop Conference in two (count them, two!) weeks and I've been working on my logline. There are lots of great descriptions of what a logline is, like the ones here and here and here. But basically, it's that one sentence description that explains what your story is about. The word logline is more of a screenwriting term, but it clicks with me, so I use it. It's your story's hook.
And it's no time to talk about the character's "journey" or "self-discovery" or "search for self-identity." In the logline, you need facts. Get specific. What's the conflict? What's the obstacle? What happens? Oh yeah, and explain it in about 100 words or less.
Here are some posts that are helping me through the process. There are two great articles (part one and part two) from Edittorrent about how to write a logline. Also helpful is Nathan's Query Letter Mad Lib. That helps you get the gist of the story down to a few lines too.