Jason Kincaid of TechCrunch writes: "Today during its keynote at I/O, Google officially announced that the latest version of Android, called Froyo, will feature tethering and wireless hotspot functionality — a big win for Android users. When we broke the news last week we questioned whether or not carriers would be able to disable or charge more for this functionality given that it was baked into the default Android OS. Unfortunately, at least as far as consumers are concerned, it sounds like carriers will get their say. In other words, expect at least some carriers to charge more for tethering."
This could work both ways. Carriers may abuse it, and charge way over the top prices for tethering, or Google could "encourage" with incentives carriers to not charge for tethering. Hopefully the latter is the actual outcome, but I'm thinking it won't be, given no carriers were named as "launch partners".