iAnnotate PDF
http://www.branchfire.com/iannotate/

iAnnotate turns your tablet into a world-class productivity tool for reading, marking up, and sharing PDF documents and Word/PowerPoint files. Every day thousands of students and professionals discover how it helps them work better. Join the more than half million users that already rely on iAnnotate to get work done. iAnnotate features the fastest PDF experience on a mobile device. Pages and graphics draw quickly and scrolling through large documents is smooth. They have worked to make iAnnotate easy to use no matter what you need to do – whether you are a student, professional, or researcher iAnnotate adapts to your needs. Easy to use tools including pen, highlighter, notes, customizable stamps, underline, strikethrough, photos, voice recording, and many more. This has been added to the tools section of Research Resources Subject Tracer™ Information Blog.