PDF-XChange Editor - The smallest, fastest, most feature-rich PDF editor/viewer available
Docr - Docr is a free app for the iPhone smartphones that lets its users scan all of their documents into sharp images and, in the end, store them as PDF files.
ScanTailor - Scan Tailor is an interactive post-processing tool for scanned pages.
Scanner Pro - Scanner Pro turns your iPhone into portable scanner in your pocket.
Briss - Cross-platform application for cropping PDF files in a simple and fast way via a GUI.
Tiny Scanner - Fast and easy to use mobile document scanner.