Tethering With A Blackberry Torch?

Just wondering if anyone knows how to tether a blackberry torch to a pc? I have unlimited internet on my phone and none on my pc. I heard there is a way to use my phone to connect to the internet on my computer for free, is this this true? And if so then How does it work? I don't want to change my internet package since I have unlimited and with ATT its almost unheard of with a smart phone.