I know there is a OpenLookup call but is this supported by Salesforce for API Usage?  If so, can anyone provide information on how to get this setup.

Looked at other Sites and blogs.. and found the below but it doesnt seem to work probably.

Code:

<TD class="labelCol  ">
<label for="tsk13" id="account_label">Account</label></TD>
<td class="dataCol col02" >
  <input name="tsk3_lkid" id="tsk3_lkid" value="{!Account_Id}" type="hidden">
  <input name="tsk3_lkold" id="tsk3_lkold" value="" type="hidden">
  <input name="tsk3_lktp" id="tsk3_lktp" value="001" type="hidden">
  <input name="tsk3_lspf" id="tsk3_lspf" value="0" type="hidden">
  <input name="tsk3_mod" id="tsk3_mod" value="0" type="hidden">
  <span class="lookupInput">
  <input tabindex="30" maxlength="80" title="Related To" 
   onchange="document.getElementById('tsk3_lkid').value='';document.getElementById('tsk3_mod').value='1';" id="tsk3" size="20" name="tsk3" 
   type="text"><a title="Related To Lookup (New Window)" 
   href="JavaScript&colon; openLookup('/_ui/common/data/LookupPage—lknm=tsk3&lkfm=editPage&lkrf=&sn=1&lktp=' + document.getElementById('tsk3_lktp').value,670,document.getElementById('tsk3_mod').value,'&lksrch=' + escapeUTF(document.getElementById('tsk3').value),'maxw')" tabindex="31" onclick="setLastMousePosition(event)" id="whtbtn"><img src="/s.gif" alt="Related To Lookup (New Window)" class="lookupPopup"></a></span><span class=errorMsg id="errorMsgAccount"></span>
</td>