synopsis is a brief (think one paragraph) description of your story. It establishes the major characters and the problem/"hook" of the story. (i.e. What's the conflict, why would the reader care?)
A logline is a tagline, a one sentence, compact, manageable synopsis to give to guys with a tight schedule. It's an infomercial in less than 25 words. It gives the main character and problem in a rapid fire "bullet" explanation.
Note that both of these should suggest the mood of the story (comedic, tragic, strange, etc.) and also hint at the theme (love, war, peace, and all that other touchy-feely crap. )
But seriously dude, eHow or wikipedia can help you out if you don't know something. (And save my poor, typed-to-the-bone fingers)
More importantly, no one is going to take you, or your story seriously if you don't have a grasp on some of the basic tools of the trade to narrative writing. Being a newbie is fine, everyone's gotta be a noob at least once, but that's also what a library is for. You should grab some books on the subject, read up to attain knowledge, and then tote it around, spouting off concieted bits of wisom at random intervals. (Like me)