Plain Text APP
Just copy the formatted text onto the clipboard, then start the app and tap the Remove Formatting button. Thats all there is to it. A widget is also provided - just drag it onto the home screen and tap it to remove formatting from the clipboard text.
The inspiration for this app was Steve Miller's Pure Text utility for WIndows (http://stevemiller.net/puretext/).
This app is licenced under the MIT licence. Source code and licence information is available at https://github.com/andyjohnson0/PlainText.