Display model URL in admin

If the model has a get_absolute_url() method, there should automatically be a 'View on site' button at the top right of the admin detail screen.

For the list view, you can easily add a method to the list of fields shown:

class MyAdmin(admin.ModelAdmin):
    list_display=('name', 'anotherfield', 'show_url')

    def show_url(self, instance):
        return '<a href="%s">View on site</a>' % (instance.get_absolute_url())
    show_url.allow_tags = True