thats if you want an official solution. check out the Droid Hacks section, people already have tethering up and running. just don't do anything crazy like download tv shows or movies.
Its actually not available yet, even if you wanted to pay for it. Its suppose to be available with the OTA update coming in December. It also costs $15 to add tethering (after paying the $30 for data to the phone) unless your on a business account, then its an extra $30. Its not cheap, but neither is providing the service. Look at ATT, they are so bogged down by the iphone they can't even offer MMS after two years!?