I was recently discussing an asterisk implementation at a 12 seat organization, and the customer had some concerns about using a more developed solution such as the Trixbox or Swithchvox products due to budgetary constraints.
He had a fair amount of Linux knowledge and had used asterisk on a limited basis at home. Because he was not completely foreign to the subject he was ready to tackle the project, but needed some additional preparation.
To aid him, I found this link, just posted a couple days ago on Youtube which gives information on setting up a dial plan:
Also, for asterisk “how to”, I have found the below link to be valuable (discovery goes to our own Cory Andrews):