2 HD 1 Apple TV

Can I use 2 external HD with 1 Apple TV with installed aTV Flash? If I buy a hub with 2 USB an use in Apple TV or in my external HD?

Thank you

Yes, multiple hard drives can be used as secondary storage if you attach a USB hub.

However, only a single drive can be used as primary iTunes storage.

USB drive basics can be seen here.

http://support.firecore.com/entries/259297-using-an-external-usb-drive-for-storage