Can't get return value from VB.NET method in Jquery using $.ajax

I'm a noob at jquery and ajax.  Bascially I have a vb.net class file that is calling some webservices.  I need to return the parsed values of the webservice calls back to the original page.  When I try it according to posted examples the return value is always null.  As a test I changed the vb.net file to return a hardcoded value and still nothing.  Does my vb file have to be a webservice?  I've seen several examples that are.  Below is my code:

VB.NET CODE
-------------------------
Imports System.IO
Imports System.Net
Imports System.Text
Imports System.Xml
Imports System.Xml.XPath 
imports System.Web.Services

Partial Class getInfo
    Inherits System.Web.UI.Page
	
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        getInfo(Request.Form(0))
    End Sub

    public function getInfo(ByVal Postal As String) as string
	return "hi"
    end function

    protected sub dosomethingelse()
    end sub
End Class


JQUERY CODE
-------------------------
<script type="text/javascript" src="/js/jquery-1.4.2.min.js"></script>

<script language="javascript">
$j = jQuery.noConflict();

function Postal()
{
	if (document.getElementById('txtPostal').value == '')
	{
		alert('Please enter a valid postal code');
	}
	else
	{
		$j.post("http://devsite/GetInfo.aspx", {postal: document.getElementById('txtPostal').value}, function(data){alert(data);});
	}
}
</script>

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