-        username = request.POST.get('username', None)
-        password = request.POST.get('password', None)
-        service = request.POST.get('service', None)
-        lt = request.POST.get('lt', None)
-
-        try:
-            login_ticket = LoginTicket.objects.get(ticket=lt)
-        except:
-            errors.append(_('Login ticket expired. Please try again.'))
-        else:
-            login_ticket.delete()
-            user = authenticate(username=username, password=password)
-            if user is not None:
-                if user.is_active:
-                    auth_login(request, user)
-                    if service is not None:
-                        ticket = create_service_ticket(user, service)
-                        return HttpResponseRedirect(service + '?ticket=' + ticket.ticket)
-                    else:
-                        return HttpResponseRedirect(success_redirect)
-                else:
-                    errors.append(_('This account is disabled.'))
-            else:
-                    errors.append(_('Incorrect username and/or password.'))
-    form = LoginForm(service)
-    return render_to_response(template_name, {'form': form, 'errors': errors}, context_instance=RequestContext(request))
+        form = LoginForm(request.POST)
+        if form.is_valid():
+            user = form.get_user()
+            auth_login(request, user)
+            service = form.cleaned_data.get('service')
+            if service is not None:
+                ticket = ServiceTicket.objects.create(service=service, user=user)
+                success_redirect = ticket.get_redirect_url()
+            return HttpResponseRedirect(success_redirect)
+    else:
+        form = LoginForm(initial={
+            'service': service,
+            'lt': LoginTicket.objects.create()
+        })
+    return render_to_response(template_name, {
+        'form': form,
+        'errors': form.get_errors()
+    }, context_instance=RequestContext(request))