Edit an xml file and save it

Use a dictionary (for my mind i prefere using plist it's a xml file but then it's easier to use it)

Property list is same as the XML file. So try to update (write data) in your plist file. And retrieve it. May helpful. Try the link...............

http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/PropertyL ists/ReadWritePlistData/ReadWritePlistData.html#//apple_ref/doc/uid/10000048i-CH 8-SW1

xml or plist , just the extension differs.(Both are Extended Markup Language).

If u want to edit it manually - u can use property list editor (which is in XCode )

or u can open with dashcode , which can be edited easily.

If ur question was to edit dynamically.

U can do that with write to file functionality.

For example u may check this.

http://www.iphonedevsdk.com/forum/iphone-sdk-development/1613-read-write-create- data-files.html