Just days after its release in the Android Market, ClockworkMod Tether has been hidden from anyone on AT&T's network. With Sprint likely to follow suit, EVO users looking to install the non-root app through the Market should probably hurry to download it.
With wireless tethering being among the top reasons most users root their device, the app actually might have worked in the carrier's favor to keep people from rooting to avoid the patently ridiculous $30+ a month limited tethering plans. Or maybe not. But either way, AT&T's move won't stop non-root tethering apps from being available; it will just make the Market not show it to their customers.
While it is a violation of your Sprint contract to use an app like this for tethering purposes, one can argue that it's also a violation of advertising laws to advertise and call it "unlimited data" and then limit how much you can use, how it's accessed, what you can see in the Market and search results, and so on.
In any case, if you're not rooted, get it while you still can, but don't use it unless you want to risk running into problems with Sprint. I personally think of tether apps like I think of spare tires, fire arms, and cats: for the most part they're useless, but in a severe bind they may come in handy.