I have no idea how to incorporate this into a web part or get a web user control to function, because this is based off of .Net 3.0 and VSEWSS 1.1 is based off of .Net 2.0. Here is how you would include a progress bar in an ASP .Net 3.5 Application or Web User Control:
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="TestingAjax.ascx.cs" Inherits="TestingAjax" %>
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel1"
UpdateMode="Conditional"
runat="server">
<ContentTemplate>
</ContentTemplate>
</asp:UpdatePanel>
<asp:UpdateProgress ID="UpdateProgress1" runat="server">
<ProgressTemplate>
<center>
<asp:Image ImageUrl="http://sptest:2/_layouts/images/gears_an.gif" runat="server"/>
<br />
<b>Creating Site...</b>
</center>
</ProgressTemplate>
</asp:UpdateProgress>
If you want you could throw in a button control and a click event. Maybe System.Threading.Thread.Sleep(1000), so that you could see the bar actually doing something. If anyone knows of an excellent way to incorporate this .Net 3.5 code into a SharePoint web part or some form of user control please let me know. If not, at least there is a nice little example on how to use something in a .Net 3.5 application with the Site Gear Picture. Enjoy.
**Update***
So I went and downloaded the ASP .Net 2.0 extensions for AJAX 1.0 and it's not working. I have the option to shove an update panel, script manager, and progress bar down. Unfortunately it does not work with the button click event, so I am going to have an AJAX ASP .Net 2.0 Mech Battle tomorrow, where I use my goddess powers to command it to do thy bidding (aka I am going to find a workaround)....