Can Asterisk be configured to take orders over the phone by using the telephone touch tone keypad and/or voice prompts?
If it can then can it be integrated to a databasde that is also online as a web page that takes orders?
This is perfectly possible to do using an AGI script. Have a look at the book Asterisk: The Future or Telephony. This is a big subject and there are so many different ways that this could work.