PdaNet
Check out this site
http://www.samsungmomentforum.com/how-to/how-to-tether/ for full instructions on how to downlaod and install PdaNet. You DO NEED TO ROOT YOUR PHONE for this to work.
I recently moved had no internet at the new house for a full week. I tethered my Moment to my server and shared the internet connection over my WiFi. My phone served as my primary internet for the entire week, and I never had any problems.