Comment by bitwize

    There was a young lady named Bright,
    Whose speed was much faster than light.
    She went out one day
    In a relative way
    And returned on the previous night.

Time flows differently depending on velocity with respect to your frame of reference. Two observers moving at different speeds with respect to each other see different time flows. At normal speeds this is negligible but at close to light speed... hoo boy. You get things like observers seeing events occur separately that occured simultaneously for their counterparts and so forth. So if you were able to send information faster than light somehow, you would be sending it from one frame of reference with one notion of time into another frame of reference with a different notion of time -- one which observes receipt of the message before it can observe the sender sending it!

It's all a big ball of wibbly-wobbly, timey-wimey stuff.