How to create a "Loading Please Wait..." screen....

Hello--

I wanted to bounce some ideas around amongst the experts in this room...

I am using MSFT IAG 2007 which allows me to "inject" code into an existing webpage.  

I have a webpage which is a Login Page for one of my clients web applications.   The webpage consist of a Username / Password and Submit button and moderate branding of the webpage.   The problem is, after the submit button is trigged it takes anywhere between (1 - 30 seconds) for the webpage to pass through to the next page.   My client requested that we "hide" this screen with a "Loading... please wait" type of deal which blocks the user from seeing anything else.

Can someone please offer me some ideas and perhaps even code to try?  I thought about using frames but it sort of creates an loop.... I tried Iframes but the user during that 30 seconds and scroll down and see the username and password fields..  

I appreciate the help.