Have you tethered yet? I tried it briefly and didn't care for it. However I have access to Wifi every 100 yards in Orlando so it really isn't necessary locally. When I travel I use hot spots and pay for access when I need it. It works out cheaper for me that way.
If you haven't tethered, the below video shows you step by step how to get a free trial for Tether. Try it before you pay for the service. You may find it works for you but the video is helpful. YouTube - How to Tether from your blackberry to mac or pc free