The Alcubierre Drive is theoretically possible, but I did not find out until yesterday that NASA is actually doing research along those lines (at this stage, they're just trying to find out if it is possible to create "warp bubbles" on a much smaller scale than a starship would require). See the video-clips on this page, and this page from NASA itself. If they can get this thing to work (and note that their projected date is no earlier than 2100) it could go 10 times faster than light -- which would still mean a 6-month trip to the nearest star, but, any planet within the Solar System could be reached in minutes.