Adobe Ideas 1.0 for iPad This free app lets you make sketches on a huge virtual canvas, zooming in and out and expanding and contracting the size of individual elements. You can import images from your iPad photo gallery, and use variable-size brushes and colors. Ideas supports layers to handle different parts of an image separately. When you’re done, you can export your sketches as PDF files, and import them to Adobe Illustrator or Photoshop for further work. It’s a terrific drawing tool, very simple but powerful, and even more remarkable for being free.