Free way to use phone as modem

[garlic]

I am getting a new Treo Pro next week, as a replacement for the 3rd refurbished Treo 800w from Sprint that didn't work correctly.

One of my chief concerns is how I will use the phone as a modem. On the 800w, I needed only to delete one registry key and everything worked great using the Internet Sharing application. On the Treo Pro, I've read somewhere that this little fix won't work. I REALLY don't feel like paying any $ to buy a 3rd-party application, though...despite the good things I hear about PDANet and wmWiFirouter. Anyone know of a free workaround?