Best way to do register a user in Django

Make two model forms, one for the User model and one for the UserProfile model.

class UserForm(django.forms.ModelForm):
    class Meta:
        model = User  

class UserProfileForm(django.forms.ModelForm):
    class Meta:
        model = UserProfile
        exclude = ['user']

Give them prefixes and display them together in the same HTML form element. In the view, check that both are valid before you save the User and then the UserProfile.

def register(request):
    if request.method == 'POST':
        uf = UserForm(request.POST, prefix='user')
        upf = UserProfileForm(request.POST, prefix='userprofile')
        if uf.is_valid() * upf.is_valid():
            user = uf.save()
            userprofile = upf.save(commit=False)
            userprofile.user = user
            userprofile.save()
            return django.http.HttpResponseRedirect(…something…)
    else:
        uf = UserForm(prefix='user')
        upf = UserProfileForm(prefix='userprofile')
    return django.shortcuts.render_to_response('register.html', 
                                               dict(userform=uf,
                                                    userprofileform=upf),
                                               context_instance=django.template.RequestContext(request))

In register.html:

<form method="POST" action="">
    {% csrf_token %}
    {{userform}}
    {{userprofileform}}
    <input type="submit">
</form>