The iPad is a window through which you can enjoy content. The clarity and interaction are really great. Why would anyone ever want to print this beautiful content? There are reasons. A boarding pass for your airline — at least until they all let you use your cell phone to authenticate and board. An email that you want to put on the kitchen table. A checklist of things to do in the garage that is going to end up with grease on it. Etc. The iPad has a few apps available for printing but they are not for the casual user. They require installing some software on your home or business LAN and that software has to be running in order to print from the iPad. Looks like Google has a better way. I just learned about this and am quite enthused about the solution.
Google Cloud Print has a simple but profound vision — enable any application (web, desktop, mobile) on any device to print to any printer. The concept is simple. An application — GMail, Safari, GoodReader, or any iPad app that has something printable — submits the print task to the Google print service.  Google Cloud Print then sends the print job to the selected printer of your choice as long as that printer is connected to the Internet via a built in network adapter and which the user has previously registered with the service.  The only catch is that the vision requires a new class of cloud-aware printers which to my knowledge are not yet available. No reason that they can’t be though and assuming Google does this in an open way, as they usually do, there would be no exclusivity and therefore other cloud services and all the printer manufacturers can participate. I suspect we will see cloud printing sooner than later. It just makes sense, just like the iPad.
Apple will no doubt have a solution also, probably with MobileMe. I was an early user of MobileMe, hoping to cut the cord with Microsoft Outlook with it,  but became quite disappointed with it. Steve Jobs made a public apology about MobileMe but it did not salvage thins for me. I moved to the Google cloud for contacts and calendar and began syncing to the iPhone over the air. It was flawless from the beginning and provided a blessing compared to Outlook. Cloud computing is clearly here to stay and it will be greatly enhanced with cloud printing. In combination with the iPad it moves the PC yet another step away from relevance. One of the final steps will be the move of iTunes to the cloud so new apps and updates can be accomplished without having to plug in to the PC or Mac.
Update June 10, 2013 : MobileMe service ceased as of June 30, 2012. You may read more about this here.