LaunchFlowFromVisualforce_Example.html

<apex:page standardController="Contact">

     <!-- When the flow finishes, the user will end up back on
          this Contact's page. This is determined by the finishLocation -->

    <flow:interview name="Contact_Update"
                    finishLocation="/{!Contact.Id}">

    <!-- The first apex:param is setting the v_ContactId variable
         in my flow to the id of the Contact -->

    <!-- You can set as many of these as you want simply by listing
         them out list this -->

        <apex:param name="v_ContactId" value="{!Contact.Id}"/>
        <apex:param name="v_ContactFirstName" value="{!Contact.FirstName}"/>

    </flow:interview>

</apex:page>