Extracting text notes from an iOS 5 backup file?
Ok I did it with iPhone Back Extractor. Lucky me the first note was that I needed

Download the free edition here: http://www.iphonebackupextractor.com/free-download/

It will locate automatically your backup folder otherwise you can select it manually, then select what you want to extract.

So, download the app, run it and then select your backup, if it has not been already found by the application itself. Then, the simplest way is to click the blue number next to 'Notes' in the available data section. You can also extract your Notes to .HTML format using the 'Extract' menu and choosing 'Notes as HTML'. You can do that for contacts, photos, calendar, location data, call history and so on.