.
you can have a look at this left - middle - right template I designed
http://213.100.118.115/phpextra/home.php
I have explained, labeled, source well for any user
It is about using % and width and height, so that it works all out
sometimes seems only trial and error and testing in different browsers (I use Opera)
will tell you IF and WHEN it works
setting height of table which is INSIDE another table to 100%
while the outer table adjusts to total main height or is set to a fixed value
A good advice:
Use table border=1 while working with code.
I sometimes temporarily even set different colors to table borders, while debugging
That way you can see how alterations effect the size of table fields
Another way is to set <td bgcolor=red>
This will color this <td> and so you can see size