After reading all of this, I felt like I would share since I deal with networking issues all day every day.
In layman's terms, here's what's really going on.
Your phone has access to the internet via the mobile network. Your mobile network does not allow people to tether. You need an application to act as a middle man. On one side, the phone sees it as an app using its internet connection. On the other side, your PC sees it as a connection to the internet. In order to accomplish this, it has to use some form of NAT (network address translation, a full description of this is beyond the scope of my post).
It is because of this that you can not simply set up a dial connection to access the internet via your phone. You must have a server which is willing to listen to your cry for a connection.
If we knew exactly what boost did to initiate the connection, and could somehow interface that using the PC it may be possible (this is how i used to tether on 1xrtt). It really doesn't make sense to even try to figure that out, since the other option is already available and works fairly well across the board.