Sprint is the only carrier with truly unlimited plans. For their smartphones, anyway. Now, it seems they want to change that with their tablets.
As you can see in the above picture, the carrier will be offering both 3G and 3G/4G plans, each with their own amounts and pricing structures. For example, 3G-only plans will offer 2GB and 1GB data plans, each of them with a $0.05 per MB overage charge. 3G/4G combo plans will offer 3GB, 5GB, and 10GB plans, with the same overage charges. You can also bundle these plans with your eligible unlimited smartphone plan, but it doesn't add any data; it just lowers your payment a little bit.
With any luck, these plans won't translate into Sprint's smartphone plan offerings. I would be severely disappointed if that happened, because Sprint, like I previously mentioned, has the only truly unlimited plans out of the four major carriers here.
Expect to see these plans once the HTC EVO View 4G is unleashed on the 24th.