How to use phone as modem?

[Long Con]

Hi, my Bell eWire modem just died, and it's going to take 3 - 5 business days for them to send out a new one... a LIFETIME!

I want to use my phone as a modem, but I don't know the steps to take. I have the Mighty ROM flashed, and when I connect the USB, there is the option to 'Use Phone As Modem', but it just says 'Check USB cable connection' under 'Status' on the Internet Sharing screen, and my laptop still has no Internet.

What do I need to do to make it work? Sorry if this has been answered in another thread, but I'm just on my phone and I could only find tethering fix stuff, not the process of hooking it up.

Please help!