Genius Scan - On The Go.
Printer Pro - Print attachments, receipts, documents, web pages from your iPad and iPhone.
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.
CalPrint - CalPrint uses your existing reminders and calendar entries on your iPad or iPhone (Exchange, iCal and Google Calendars etc.
Tiny Scanner - Fast and easy to use mobile document scanner.
Air Sharing - Air Sharing lets you bring your documents with you — without bringing your computer.