Reading and Readability in iOS Devices

Reading PDFs in iOS devices like iPhone and iPod Touch is not easy, because the text is too little and the screen is too small. Zooming-in may require scrolling the page horizontally back and forth. This is because the text in PDF cannot be subjected to word wrapping. The ePub format has gained popularity because unlike PDF it is designed for reflowable content. Meaning, the long lines will eventually move down (reflow) without creating horizontal scroll bars. What tools can we use to convert PDF or webpages to ePub?