I have been looking for something like this for ages! I used to be able the use the internet from my phone, on my laptop, but my network (not T Mobile) put a stop to it and they now have software in place that knows when you are trying to tether. You get an instant 30 minute ban from the internet on your phone, if you try.
It would be GREAT if someone could come up with something that can fool the network into thinking you are not tethering! If someone does come up with something, don't post how you did it, because the network will find out and close the loop hole. Just post the zip or instructions how to get it to work etc.