LTE data on the new iPad can get expensive, but at least Verizon's cutting you a break and including tethering in the price of your iPad data plan. Otherwise, it would be a $20 charge for tethering, along with an extra 2GB of data.
We've reached out to AT&T to see if it'll include tethering gratis, but right now it seems like it's not going to happen. Which, when combined with the $15 for 250MB lowest-tier plan compared to the $20 for 1GB, that looks a little bleak, but you do get an extra GB at the $30 tier. So AT&T still makes sense if you only want ~3GB of data and don't care about tethering.
I'd just point out, though, that if you're looking for an LTE hotspot option, it might make more sense to just get an LTE MiFi and use that for your phone, tablet, and laptop. That way you don't have to lug out the tablet if you need mobile internet on your laptop or phone. The battery life isn't as good as an iPad, but it was good enough to keep Gizmodo running at CES this year. Just something to think about! [GottaBeMobile]
Update: Here's AT&T's official comment: "We are working with Apple to enable this feature in the future, but we currently do not offer it."