Yes, you just open up customer/main/product.tpl and move things around. You'll need to know a bit of html to understand the table layout. Each 'module' is a line of code, so if you wanted to switch detailed images and send to friend, replace this:
{include file="customer/main/send_to_friend.tpl" }
{if $active_modules.Detailed_Product_Images ne ""}
<P>
{include file="modules/Detailed_Product_Images/product_images.tpl" }
{/if}
with this:
{if $active_modules.Detailed_Product_Images ne ""}
<P>
{include file="modules/Detailed_Product_Images/product_images.tpl" }
{/if}
{include file="customer/main/send_to_friend.tpl" }
Moving to Template Editing.