When trying to downgrade an iPad from 4.2beta to 3.2.2 directly via iTunes, I just get a non-descript error message. However, there is a nice howto out there, which describes this.
How to make Hybrid Apps that run on 3.1 and higher devices (iPod, iPad and iPhone)
This fantastic blog entry helps you to actually use the UserInterfaceIdiom message, which is only available in iOS 3.2 and higher. This way, you can actually build a hybrid iPad / iPhone app that even runs on the original iPhone, which only comes with iOS 3.1 at best.
Nice things about the iPad
Well, one nice about iPad development is that porting your app is pretty easy. Took me 1 minute exactly. Sure, you have to re-tweak your UI, but the OpenGL ES rendering is instantly high-res.
iPad WiFi problems
Yes, it’s true. The iPad WiFi problems are definitely there. I currently have one iPad lying around here, which has obscenely bad WiFi performance: bad signal, slow, disconnects. The eduroam node I am using is 6m away, almost line of sight (two open doors).