This interactive Google Maps mashup shows how much different parts of the world will get flooded by a
1-7 1-14 meter rise in sea level. Navigate to the part you’re interested in and tell the app how much to raise the ocean, and a blue overlay covers up the parts that will get inundated. Scary.
There’s a disclaimer by the mashup’s developer which states that this map isn’t necessarily very accurate, and takes no account of tidal changes (obviously an important detail).
Another flood zone map, which is less Web 2.0-ish but perhaps more accurate, puts flooded zones in red: Climate Change and Sea Level (from the University of Arizona).