updated 08:20 pm EST, Wed March 7, 2012
iPad LTE technology explained
(Update: AT&T clarification) Apple's store page for the new iPad has confirmed expectations for US-based LTE data plans. Both AT&T and Verizon users will have the option of 2GB or 5GB of prepaid data for $30 and $50 for each month, respectively. AT&T users will still have the option of a very light $15, 250MB plan, while Verizon users can get 10GB a month if willing to pay $80.
Although intended for the US and Canada, the LTE access isn't strictly confined to North America. Germany and other countries with early LTE deployments should theoretically have the option of using the new iPad at 4G speeds on the 2,100MHz band. Apple isn't removing 4G from international shipments and could enable access as carriers add LTE over time.
Verizon-only editions won't have LTE in other countries so far owing to its 700MHz-only access. Both its version and the AT&T model should still have world roaming on HSPA+ 3G.
In the meantime, AT&T has added that those iPad owners grandfathered into unlimited data plans aren't being throttled as they are for smartphones. An explanation hasn't been given, although it's suspected their lower device volumes reduces their effect on the network.
Update: AT&T added that Apple's page is slightly out of date and that its $30 plan offers 3GB, not 2GB.