I think what you're looking to do is to have an update progress message display. Microsoft Ajax has this already implemented. .Net 1.1 can use the ajax framework and it's very easy to drop an update panel and an update progress control on a page and have the functionality that you're looking for. Here is a link to a simple example.
Offical page for MS Ajax
Update Progress Demostration
Web.config setup:
<add tagPrefix="ajax" namespace="AjaxControlToolkit"
assembly="AjaxControlToolkit" />
<add tagPrefix="asp" namespace="System.Web.UI"
assembly="System.Web.Extensions, Version=1.0.61025.0,
Culture=neutral,
PublicKeyToken=31bf3856ad364e35" />
And the DLL's to include in the BIN folder:
AjaxControlToolkit.dll
AJAXExtensionsToolbox.dll
Good luck and hope this helps some.