Laptop implies that the machine can be placed in the lap while sitting. There have been some recent cases where young execs have had their family jewels burned by the heat from modern-day notebooks. Ouch.
They are meant to be different, I think the term notebook was originally used to signifiy that the laptop was smaller than a standard laptop. However manufacturers tend to just stick the name on what they fancy these days.
In essentce however they are indeed the same, it would be the last think (if you did at all) to consider when looking at them.