here is a simple example:

  <div style="text-align: center; font-family: georgia, arial; font-size: medium; color: #ffffff">
    <a name="eMail">
        <a href="mailto:someone@somesite.com"><img src='http://www.grumpysgoodies.com/images/smileys/wave_lg_wht.gif'></a><br />";
    </a>
  </div>

I actuallty made is a bit fancier by including a script that grabs the page title and passes it to the buyers email program filling it into the subject line...

And yeah that example is for email but an anchor tag is an anchor tag and the target would just be whatever URL you need...I can post the whole leetle snippet if ya wanna see what I did...it's not perfect at all because I need to add an "onclick" behavior instead of building the link on page load...but, eh, whenever...hehehehe... :D