iPad users will get one major OS upgrade for free
iPad users will have to purchase some OS updates aired with the release of the iPhone OS 3.2 software development kit, according to documentation accompanying the new SDK.
As noted by "DailyTech" (http://www.dailytech.com/IPad+Users+Get+One+Free+Major+OS+Upgrade+and+Th...), the documentation has this to say:
Apple will provide you any iPad OS software updates that it may release from time to time, up to and including the next major iPad OS software release following the version of iPad OS software that originally shipped from Apple on your iPad, for free. For example, if your iPad originally shipped with iPad 3.x software, Apple would provide you with any iPad OS software updates it might release up to and including the iPad 4.x software release. Such updates and releases may not necessarily include all of the new software features that Apple releases for newer iPad models."
In other words, with the iPad, Apple will be giving users one free, major OS upgrade. After that users will be on their own and will be forced to pay to upgrade the OS. Upgrades will likely be priced similar to those on the iPod touch, at about US$10, says "Daily Tech."