Visual force page dynamically showing related contacts of an account

Hi s_mac,

The below solution might help you out :

Visual Force Page Code:
// Here standardController=”account” used to display account details dynamically.
<apex:page standardController="Account" recordSetVar="accounts" tabstyle="account" sidebar="false" extensions="DisplayContact" >
  <apex:pageBlock title="Account" >
    <apex:form >
      // Here your account details is shown using standard  controller.
      <apex:pageBlockTable value="{!accounts}" var="a" id="list">
        <apex:column headerValue="Account Name">
// Here is the account name display, when you click on the name of the account then it will get the Id and display the contact under the account list
        <apex:commandLink rerender="contactDetails" value=" {!a.Name}" action="{!ContactLists}">
// Getting the account id that retrive the contact details
         <apex:param name="id" value="{!a.id}"/>
       </apex:commandLink> 
         </apex:column>
        <apex:column value="{!a.type}" />
        <apex:column value="{!a.billingstreet}"/>
        <apex:column value="{!a.billingCity}" />
        <apex:column value="{!a.billingCountry}" />
        <apex:column value="{!a.billingPostalCode}"/>
      </apex:pageBlockTable>
    </apex:form>
  </apex:pageBlock>
  <apex:pageBlock title="Contact">
   <apex:outputPanel id="contactDetails">
// Display contact list according to their Account Id.
     <apex:pageBlockTable value="{!conList}" var="con" id="conlist" title="Contact">
     <apex:column value="{!con.Name}"/>
     <apex:Column value="{!con.Phone}" />
     <apex:Column value="{!con.Email}" />
     </apex:pageBlockTable>
    </apex:outputPanel>
  </apex:pageBlock>
</apex:page>

Apex Class:
public with sharing class DisplayContact {
    public List<Contact> conList {get;set;}
    public DisplayContact(ApexPages.StandardSetController controller) {
    }
    public PageReference ContactLists()
    {
// Checking account id is not null.
    if(ApexPages.currentPage().getParameters().get('id') != null)
      conList = [Select id,Name,Phone,Email from contact where accountId =: ApexPages.currentPage().getParameters().get('id')];
     return null;
    }   
}