Marco Arment has released details on the upcoming iPad version of his popular Instapaper offline reading app. In a blog post on his site, Arment confirms that Instapaper is coming to the iPad “possibly even on day one.” The new design is described as very similar to Instapaper Pro with “slight interface tweaks and redesigns where appropriate.” The most significant visual changes have been made to the landscape view with the folders now appearing in a sidebar to the left of the main content listing. Arment mentions that he had originally planned to wait to release a native version of Instapaper until he actually had an iPad available to work with, however after seeing the pixel-doubled iPhone version in the iPad simulator he found it “completely unusable.” As a result he decided that a native iPad version was necessary sooner rather than later. Arment also plans to make Instapaper Pro a universal iPhone and iPad application as he doesn’t “want anyone subjecting themselves to the iPhone edition in pixel-doubled mode.” The universal version will be a free upgrade for existing Instapaper Pro users and will allow new users to use a single app on either the iPhone or iPad without having to purchase separate versions. Arment indicates that he plans to “experiment with more radical interface changes in the future” once he’s actually used an iPad, but he felt that having an iPad-native Instapaper app available at launch was more important than waiting to perfect the app. Additional details and screenshots can be found at the Instapaper Blog.