The iPad that was recently demoed was running iPhone OS 3.2 Beta. This OS is only available for iPad’s at this time, but you can count on Apple to release it for iPhones & iTouch’s.  The ability to multitask, twitter using qTweeter, Tethering and, also since their is a 3G iPad model already it wont be hard for Cydia developers to develop phone calling / SMS capabilities over-the-air to the iPad. Hopefully we can count on George Hotz and the iPhone Dev-Team to jailbreak (iPhone and iPod touch on OS 3.1.2 using blackra1n, PwnageTool, redsn0w, and sn0wbreeze) the iPad.