use the DOM.
webbrowser.document.getelementbyid("usernameinputboxid").innerText =
textbox1.textl;
webbrowser.document.getelementbyid("passwordinputboxid").innerText = textbox2.textl;
webbrowser.document.getelementbyid("loginbuttonid").invokemember("click");
then you can create an xml file that maitains the element ids, what values to put in them, wich button to click and automate the whole thing.
my 2 cents anyway