def register(request):
    if request.method == 'POST':
        form = UserCreationForm(request.POST)

        if form.is_valid():
            message = None

            form.save()

            username = form.cleaned_data['username']
            password = form.cleaned_data['password1']

            user = authenticate(username=username, password=password)

            first_name = form.cleaned_data['first_name']
            last_name = form.cleaned_data['last_name']
            email = user.email

            # If valid new user account
            if (user is not None) and (user.is_active):
                login(request, user)
                message = "<strong>Congratulations!</strong> You have been registered."

                # Send emails
                try:
                    # Admin email
                    pk = None
                    try: pk = User.objects.filter(username=username)[0].pk
                    except: pass

                    admin_email_template = loader.get_template('accounts/email_notify_admin_of_registration.txt')
                    admin_email_context = Context({
                        'first_name': first_name,
                        'last_name': last_name,
                        'username': username,
                        'email': email,
                        'pk': pk,
                    })
                    admin_email_body = admin_email_template.render(admin_email_context)
                    mail_admins("New User Registration", admin_email_body)

                    # User email
                    user_email_template = loader.get_template('accounts/email_registration_success.txt')
                    user_email_context = Context({
                        'first_name': form.cleaned_data['first_name'],
                        'username': username,
                        'password': password,
                    })
                    user_email_body = user_email_template.render(user_email_context)
                    user.email_user("Successfully Registered at example.com", user_email_body)
                except:
                    message = "There was an error sending you the confirmation email. You should still be able to login normally."
            else:
                message = "There was an error automatically logging you in. Try <a href="/login/">logging in</a> manually."

            # Display success page
            return render_to_response('accounts/register_success.html', {
                    'username': username,
                    'message': message,
                },
                context_instance=RequestContext(request)
            )
    else: # If not POST
        form = UserCreationForm()

    return render_to_response('accounts/register.html', {
            'form': form,
        },
        context_instance=RequestContext(request)
    )

pk = None
try: pk = User.objects.filter(username=username)[0].pk
except: pass

try:
    user = User.objects.get(username=username)
except User.DoesNotExist:
    user = None

try:
    ... a line of code that can generate exceptions to be handled ...
except SomeException:
    ... handle this particular exception ...
else:
    ... the rest of the code to execute if there were no exceptions ...

def register(request):
    if request.method != 'POST':
       form = UserCreationForm()
       return render_to_response('accounts/register.html',
                                 { 'form': form, },
                                 context_instance=RequestContext(request)
                                 )

    form = UserCreationForm(request.POST)
    if not form.is_valid():
       return render_to_response('accounts/register.html',
                                 { 'form': form, },
                                 context_instance=RequestContext(request)
                                 )
    ...