Complete beginner to jQuery! Help! Help! Help!

Complete beginner to jQuery! Help! Help! Help!

I have been trying to take one small step at a time in learning jQuery... The first program I wrote is pasted below:
The problem I am facing is when I run the applciation and click the button I have an error dialog pop up saying --> "Microsoft JScript runtime error: Object doesn't support this property or method" and pointing to this line -->   $("div").addclass('color');
I have no clue how to go about it.. Please Help!!!


<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="jQueryTestProject._Default" %>
<html>
<form runat="server">
    <script src="JavaScript/jquery.js" type="text/javascript"></script>
    <script src="JavaScript/jquery-1.3.2.min.js" type="text/javascript"></script>
    
    <style type="text/css">
        .color 
        { background-color:Black;
          border: solid 5px red;
            }
        #effects
        {
            height: 155px;
        }
    </style>
    
    <script type="text/javascript">
        $(document).ready(function() {
            debugger;
            $("#btnrun").click(function() {
                $("div").addclass('.color');
            });
        });
    </script>

    <asp:Button id="btnrun" runat="server" Height="60px" Width="314px" />    

    <div runat="server" id="effects">
       
    </div>
    </form>
    </html>