On my desktop computer, I basically tried to follow the instructions on
this page at www.booststuff.com.
However, it did not work exactly as described, because
1. I already had the USB drivers installed.
2. (more importantly) On my cellphone, I had the USB Reader mode enabled. So when I connected the phone to the computer, it was just acting like a USB drive instead of a modem.
Because of #2, the network connection I had created based on the instructions kept trying to use my regular dial-up modem instead of using the cellphone as the modem. So I temporarily disabled the dial-up modem, and manually added a new modem entry for "Motorola IDEN USB modem" under Control Panel - Phone and Modem Options. But when trying to connect with that modem entry, it still wasn't working. I kept getting the error "Error 692: There was a hardware failure in the modem (or other connecting device)".
To correct #2, on the phone I had to open the menu item
Settings - Memory Card - USB Connection and change the selection from "Reader Enabled" to "Reader Disabled".
Once I had done this, then when I reconnected the phone to the computer, I got the popup "Found New Hardware (Motorola iDEN USB Modem)" and XP did whatever was necessary so that the phone could be used as a modem.
Note: With this tethering, the cellphone is not used as a dial-up modem, rather it provides the connection to the internet which is already available on the cellphone.
Then I still was getting the same error, because the modem entry I had set up manually was using COM2 (since I didn't know which port to select when I set it up). Once I changed it to COM3, the tethering worked fine.
On my laptop, getting the tethering to work was much easier. However, based on how I had done it on my desktop, I thought I had to set up the modem manually on the laptop too. That presented a problem, as the wizard didn't have any ports listed for selection. So I wasn't able to add the modem manually. The thing to keep in mind is that once you have the drivers installed, when you connect the phone to the computer (with the phone *not* in USB card reader mode), the modem entry gets added automatically - you shouldn't have to add the modem entry manually. The Motorola driver download page makes it sound like the driver installation will prompt you to connect the phone to the computer. But I didn't get any prompt. So once the drivers are installed, you just connect the phone to the computer and let the device be discovered.
As I mentioned before, the internet speed on Boost is relatively slow - as slow or slower than dial-up. So I'm not planning on using the tethering except on rare occasions. But I tried out Opera 10 with Turbo enabled on my laptop, and it worked well. It's still like dial-up used to be though, where you have to wait a while for the pages to load.
.
Now, with Q's cellphone, a Clutch i465, we had a different problem. We were trying to install Opera mini on it. That phone doesn't even have a USB card reader mode. But when we connected the phone to the computer, we didn't get the sound you get when you connect a USB device. Turns out that the plastic part of the plug on the Rocketfish universal USB to micro-USB cable we had bought was too big - it was preventing the micro USB plug from going all the way into the phone socket. So it looked like it was connected, but it wasn't really.
Q tried another cable which had the same problem, so now we've ordered one which is made specifically for the i465.