You can use these apps (search apps in odoo apps by names provided below) to change the whole login page style.

Moreover, these apps provide the ability to define your own favicon and logo as you wish.

Apps Name:

Minimalist Login Form

Creative Login Form

Advanced Login Form

Thanks Alex,

I do not know how to program a controller. Review the documentation to get an idea. Any suggestions to start?

You just need to have a controller for that URL route with auth="user", like:

import openerp
from openerp.addons.web import http
from openerp.addons.website.controllers.main import Website
class ContactController(openerp.http.Controller):
    @http.route(['/page/contactus'], type='http', auth="user", website=True)
    def contact(self, **kw):
        return Website().page(**kw)

Hope that help you

Interesting Note: website=True makes a redirect to attach the lang value to the url when your website allow and have multiple langs setted