How do i make my pc work as a phone when plugged into a phone jack?

I'm using the Eee PC running Windows XP and when i have my PC plugged into the phone jack, i want it to work as a fully operational phone. Do you know how i could do that?How do i make my pc work as a phone when plugged into a phone jack?
i'm not sure if you can either, but i saw an infomercial for some adapter thing that i think will work if you have internet.





just found it :)


http://www.cuphone.com/products/usb_to_rj11/index.htmHow do i make my pc work as a phone when plugged into a phone jack?
i dont think you can do that, there are numerous phone calling services and programs that work through the internet, but not through a regular phone line