"iAnnotate turns your tablet into a world-class productivity tool for reading, marking up, and sharing PDF documents, Word/PowerPoint files, and images. 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. "
The site says that:
"Upload and share your PowerPoint & Keynote presentations, Word & PDF documents on SlideShare. Add audio to make a webinar. Capture leads with your presentations"