Support > Mobile Devices
Tethering is a capability that allows your phone or smartphone to be used as a modem to connect your laptop to the internet. Sometimes, the smartphone just isn't enough to get real work done, and there is often no need to purchase a special laptop modem and separate plan along with the associated monthly fee.
Vendor Options
Many wireless vendors do offer tethering options with some phones. Sprint, for example, offered a "phone as modem" service when I used a Palm Treo. Other vendors may offer a similar add-on plan for your device so check with them.
Third Party Options
Check your wireless carrier's service agreement, they may not officially sanction these options, but they do work!
All these options require connecting a cable to your laptop (or bluetooth where supported, generally not as good). Watch for certain Android models to begin supporting WIFI hotspots -- use your laptop WIFI connection to connect to the phone.
When tethering without a carrier sanctioned plan, data limits of your phone's internet plan will apply. If you use a 3rd party tethering program without a plan from your carrier, do not abuse the capability as it is easier with a laptop to download lots of files.