TWebBrowser - simulate key press on HTML page?

Thanks to the tip in the SwissDelphiCenter...automatic fill out HTML forms
with TWebBrowser in the forum i've satisfied my first question. Next is how
to locate a button on a HTML page and simulate pressing it? This is in
reference as to filling out the login name and password on a page then
pressing the Submit button or Login button. Any help or code would be

Charlie Chambers