Well you have a few choices.
You can hire someone. If you have a "pennysaver" or similar local advertising type paper, look in there for someone who installs telephone lines/jacks.
If you are handy and can work with electrical tools you can install it yourself. The box that the installer put on the outside is know as an NID (Network Interface device) There are normally two parts for this, the service provider side (SBC/ATT) and the customer side. The customer side will open by loosening the screw and you will see the connection point. Here is a link to a brief page and an illustration.
You would then run a cable to each location where you want a telephone connection and terminate it at a jack.
We also have a book available on-line for residential cabling, here is the link to the book.
Joseph Golan, RCDD