[SalesForce] Not able to add fields in Related list for a page layout

Assuming you are using the Case standard controller you should simply be able to use an apex:relatedList tag on your Visualforce page.

<apex:page standardController="Case">
    <apex:relatedList list="CaseArticles"/>
</apex:page>

If you're not using the standard controller then you'll have to define the subject attribute for this to work.

Controller:

public class MyController 
{
    private final Case aCase;

    public MyController() {
        aCase = [SELECT Id FROM Case 
                   WHERE Id = :ApexPages.currentPage().getParameters().get('id')];
    }

    public Case getCase() 
    {
        return aCase;
    }
}

Visualforce Page:

<apex:page controller="MyController">
    <apex:relatedList subject="{!Case}" list="CaseArticles"/>
</apex:page>

See here for more information on the apex:relatedList tag: http://www.salesforce.com/us/developer/docs/pages/Content/pages_compref_relatedList.htm

There are 2 ways :

• Formula field
  
• Custom Inline VF page
  

If you are ready to compromise on related list field visibility and prioritize reports, then its possible on reports without creating any new field.