Magento 1.8 – How to Add ACL in Custom Module

I created custom module in magento. I created that menu under customer menu. I need to add acl for custom module. I need to know that how to create acl in custom module i m giving here my config.xml…

my config.xml
------------------
<?xml version="1.0" encoding="UTF-8" ?>
<config>
    <!-- module configuration -->
    <modules>
        <Webcreon_Seller>
            <version>1.0.0</version>
        </Webcreon_Seller>
    </modules>
    <!-- module configuration end -->
    <frontend>
        <routers>
            <seller>
                <use>standard</use>
                <args>
                    <module>Webcreon_Seller</module>
                    <frontName>seller</frontName>  
                </args>
            </seller>
        </routers>
     <layout>
            <updates>
                <seller>
                      <file>sellerform.xml</file>
                </seller>
            </updates>
       </layout>
    </frontend>
    <admin>
     <routers>
         <seller>
            <use>admin</use>
            <args>
               <module>Webcreon_Seller</module>
               <frontName>adminseller</frontName>
            </args>
         </seller>
      </routers>
 </admin>
 <adminhtml>
   <layout>
      <updates>
          <seller>
              <file>sellerform.xml</file>
           </seller>
      </updates>
   </layout>
   <menu>
      <customer translate="title" module="adminhtml">

         <sort_order>100</sort_order>
         <children>
             <set_time>
                   <title>Seller List</title>
                   <action>adminseller/adminhtml_index</action>
              </set_time>
          </children>
       </customer>
    </menu>
</adminhtml> 

    <global>
        <blocks>
            <seller>
                <class>Webcreon_Seller_Block</class>
            </seller>
         </blocks>
         <helpers>
            <seller>
                <class>Webcreon_Seller_Helper</class>
            </seller> 
        </helpers>
              <models>
          <seller>
                <class>Webcreon_Seller_Model</class>
                 <resourceModel>seller_mysql4</resourceModel>
            </seller> 
            <seller_mysql4>
             <class>Webcreon_Seller_Model_Mysql4</class>
             <entities>
                 <seller>
                   <table>db_vendor</table>
                 </seller>
              </entities>
          </seller_mysql4>
        </models>
        <resources>
        <!-- connection to write -->
        <seller_write>
            <connection>
                <use>core_write</use>
            </connection>
        </seller_write>
        <!-- connection to read -->
       <seller_read>
          <connection>
             <use>core_read</use>
          </connection>
       </seller_read>
       <webcreon_seller_setup>
            <setup>
                <module>Webcreon_Seller</module>
            </setup>
        </webcreon_seller_setup>
</resources>
<rewrite>
    <sellercreate>
         <from><![CDATA[#^/seller[\/]?$#]]></from>
         <to><![CDATA[/seller/seller/sellercreate/$1]]></to>
         <complete>1</complete>
      </sellercreate>
</rewrite>
</global>


</config>