Ubuntu Networking :: "redirect" The Connection And Use Telephone As Proxy?

What I want to do is to share the internet connected to a computer with a telephone, over another telephone which is permanently connected to the pc.The thing is, that some guys found a way of making this on windows, in fact, I already set it up on xp and works like a charm, it involves configuring in a certain way the telephone,d to use 2 programs. One is CCProxy, which redirects the internet connection to the telephone, and another one, which updates the IP adress of the telephone connection to dyndns, so that I can put that adress on my second telephone as proxy, and this way, surf on the net through my home internet on the telephone anywhere. Tricky right?

Now, the thing is I don't like at all booting windows only for sharing internet with my telephone. So I want to do it in linux. I use Ubuntu and Puppy linux home.I tried setting up the connection to the modem with wvdial, and... I got connected! But hey, when I connect to the telephone, I lost my internet connection (main, cable based, the pc connection) :-S. I mean, somehow, the "active" connection for the browsers and all the internet programs is now the connection I have made with my telephone, which is plugged to the computer.Now my objective here is that NO CHANGE of active connections get done when I start the connection to the phone, and then, get a program like CCProxy, and a dyndns updater for sharing the internet connection on the pc, to the connection made on the telephone-modem wired to the computer.Am I clear? I know it is confusing, and it took me weeks to understand how it works and get it done in windows. But now... Ubuntu is what I want.