Dukai |
The way I read it, you don't take a TWF penalty for Flurry, but Flurry doesn't grant additional attacks while wielding two weapons. However, should you take the TWF feat, I would assert that you could take the appropriate penalties and utilize TWF while making a flurry. It is not explicitly stated that you cannot use TWF just that Flurry doesn't grant any additional attacks for using multiple weapons but also doesn't impose a penalty for using those weapons.