Recently, I connected my Pre to my computer (I'm running Windows 7), and the Action Center came up with a prompt that said "Install your USB modem driver" (see screenshot below). I clicked on it and an "Action Center Solution" came up that said "Click to download and install the new driver from the
Sprint website" (see screenshot below). I followed the instructions Windows provided to no avail. Naturally I was disappointed.
However, I do think that this provides evidence that the Pre will eventually support tethering. After all, Windows recognized that the Pre required Sprint drivers. Since the telecommunications-carrier information is irrelevant for the normal syncing/USB/charging data transfers, it is clear that there is some communication going on between the Pre and computer that extends beyond the normal exchange of information.