It is easy to visualize the modules positions in your Joomla 1.6 template by enabling the option from the Joomla 1.6 admin area->Extensions->Template Manager->Options. Make sure that the Preview Module Positions option is Enabled.

Then add the following code in the end of your web site URL:

?tp=1

For example, if your web site can be opened through:

http://www.yourdomainname.com/joomla16/index.php

Use the following syntax:

http://www.yourdomainname.com/joomla16/index.php?tp=1

This will visualize the template's modules positions.