Bootstrap3 Bundle for symfony2
You are looking for MopaBootstrapBundle which integrates twitter bootstrap in your Symfony2 project (form, menu...)
Github: https://github.com/phiamo/MopaBootstrapBundle
Docs: https://github.com/phiamo/MopaBootstrapBundle/blob/master/Resources/doc/index.md
As of Symfony 2.6, Bootstrap support for forms comes standard: http://symfony.com/doc/current/cookbook/form/form_customization.html#what-are-form-themes
Just update your config.yml to use it:
# config.ymltwig: # ... form_themes: - bootstrap_3_layout.html.twig
Have fun!