you have given fixed width in div id as block 1 remove it and use float: left in css
and your code will be as follows:
following changes are in
remove div's width.
give style to i frame and set is as float:left
<iframe width="425" height="350" frameborder="0" scrolling="no" marginheight="0" marginwidth="0"
and in form also give it style and set it as a float:left
<form method = "post" action = "ContactServlet" style="float:left;">