While not likely, either the iPad or the iPhones may have the hardware already, and will just require a software update to make it work.
You guys are confused.
ATT will be upgrading to HSDPA, this will give current iphone 3GS iphones speeds of up to 7.2mbps.
Now when att finaly upgrades to LTE (4G) non of the current iphones will work with that and new ones must be made that support it.