After some confusion surrounding the release date of the 3G-capable iPad involving a May 7th "Ships By" date at the Apple Store, Engadget confirms today that Apple has announced April 30th as the official release date of the 3G iPad.
The May 7th date confused customers who pre-ordered the device and received an email informing them of a "late April" delivery date. It seems like Apple is still on track to deliver in April, albeit as "late April" as you can get.
AT&T will be offering a $29.99/month unlimited plan for the device, much like the iPhone's plan. A 250MB plan will be available for $14.99/month, and the device will come unlocked by default. There is no contract, so you're free to take it to any other GSM carrier that will support the "Micro SIM" technology Apple is implementing in the iPad.
This is all for the American release of the product. Apple has yet to release the iPad, 3G or no 3G, to international markets, and now it seems that American customers will have the 3G option before international users get any device at all. This could mean that the 3G version will be released alongside the wifi-only version internationally, but there's no official confirmation on that.