Earlier we heard that the iPad OS 3.2 was made available to developers, but now we're hearing about the fine print in the licensing agreement of the OS:
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.
This appears to mean that you'll receive your first major update for free, but will pay for anything beyond that. It feels a bit similar to how OS updates were handled with the iPod touch, so nothing particularly surprising or crazy—just another charge.