Magento 菜单加上首页比较简单，\magento\app\design\frontend\base\default\template\catalog\navigation\top.phtml

打开top.phtml

<ul id="nav">
  <?php echo $_menu; ?>
</ul>

改成

<ul id="nav">
  <li><a href="<?php echo $this->getBaseUrl() ?>"><span>首页</span></a></li>
  <?php echo $_menu; ?>
</ul>

就是添加了一个首页的li。
给top link加首页的话，要在customer.xml里修改，把49行的

<default>
   <!-- Mage_Customer -->
   <reference name="top.links">
     <action method="addLink" translate="label title" module="customer"><label>My Account</label><url helper="customer/getAccountUrl"/><title>My Account</title><prepare/><urlParams/><position>10</position></action>
    </reference>
</default>

改成

<default>
   <!-- Mage_Customer -->
   <reference name="top.links">
   <action method="addLink" translate="label title" module="customer"><label>Home</label><url></url><title>Home</title><prepare>true</prepare><urlParams/><position>5</position></action>

     <action method="addLink" translate="label title" module="customer"><label>My Account</label><url helper="customer/getAccountUrl"/><title>My Account</title><prepare/><urlParams/><position>10</position></action>
    </reference>
</default>