Apple is set to release iOS 4.2 in November this year, however it’s an iPad only firmware and brings all the iOS 4 features such as printing, multitasking etc. to the iPad. The most interesting new feature is AirPlay, it allows you to stream music and video straight to your iPad over WiFi (with an iPad even acting as host for the new Apple TV).
As mentioned before printing has been brought to iOS 4 with the iPad using the Printer Center applet that sits in the dock and lets you manage print jobs.
Sam's Blog 