<apex:page standardController="Account" contentType="application/vnd.ms-excel#FILENAME.xls" cache="true">
   <apex:pageBlock title="Hello {!$User.FirstName}!">
      You are viewing the {!account.name} account.
   </apex:pageBlock>
   <apex:pageBlock title="Contacts">
      <apex:pageBlockTable value="{!account.Contacts}" var="contact">
         <apex:column value="{!contact.Name}"/>
         <apex:column value="{!contact.Email}"/>
         <apex:column value="{!contact.Phone}"/>
      </apex:pageBlockTable>
   </apex:pageBlock>
</apex:page>

http://blog.sforce.com/sforce/2008/12/visualforce-to-excel.html

Credits to Sati Hillyer &  Jeff Douglas

Visualforce to Excel

Other