Moving / Removing Callouts on the left / right columns

This is a pretty easy task, but finding them required a small bit of digging (as usual).

My first recommendation when trying to find any thing in the front end is to turn on Template Path hints in the admin section

   1. Admin > System > Configuration
   2. Switch your "Current Configuration Scope" to your store (’Main Website’ on a stock build)
   3. Click on the Developer Tab (bottom left) and find the Debug area
   4. Template Path Hints: Yes (also might want to add Block Names to hints)

You will find that the template files (phtml files) which include the html for the callouts are located at:
app/design/frontend/*/*/template/callouts/right_col.phtml
app/design/frontend/*/*/template/callouts/left_col.phtml

You will also find that the block is being added onto your Magento install via catalog.xml
app/design/frontend/*/*/layout/catalog.xml

For the right column:

<reference name="right">

<block type="core/template" before="cart_sidebar" name="catalog.compare.sidebar"

template="catalog/product/compare/sidebar.phtml"/>

<block type="core/template" name="right.permanent.callout" template="callouts/right_col.phtml"/>

</reference>

to

<reference name="right">

<block type="core/template" before="cart_sidebar" name="catalog.compare.sidebar"

template="catalog/product/compare/sidebar.phtml"/>

<!--<block type="core/template" name="right.permanent.callout" template="callouts/right_col.phtml"/>--> <!-- or delete this line altogether -->

</reference> 

You can do the same for the left callouts