Magento:: Set products per column, page in category listing

>> Go to Admin=>Manage categories=> Then click on the custom design tab
      If you want to display 20 products per page, with 5 columns. Then you have 5 products on each row.


<reference name="product_list">
     <action method="setColumnCount"><columns>5</columns></action>
</reference>


<reference name="product_list_toolbar">
     <!-- Your default products count : 10 -->
     <action method="addPagerLimit"><mode>grid</mode><limit>10</limit></action>        
      <!-- Your new products count : 20 -->
     <action method="addPagerLimit"><mode>grid</mode><limit>20</limit></action>        
      <!-- The total number of products to display per page -->
     <action method="setDefaultGridPerPage"><limit>20</limit></action>
</reference>