title: Add column to Magento admin catolog > manage products
body: <p>Hi I want to add a column to the catolg > manage products section (not the product but the list of products), this column needs to list any related products the product has identified with it - maybe by sku or name - no preferance there.</p>
  
  <p>I added a column for manufacturer but forgot where i obtained the code from.</p>
  
  <p>thanks</p>