Not sure what could have caused that error in replying to a previous
post. However, you're right - placing the \caption[...]{...} command
at the top places the caption at the top of the figure/table.
Similarly, placing it at the bottom would drop the caption at the
bottom of the figure/table. There are also many more formatting
options available for styling your floating environment captions. This
is possible through the caption package, available online via CTAN
from
http://tug.ctan.org/pkg/caption
Werner