There is a command line utility for iPhone called
plutil
and you can convert the binary xml file to text xml file in iPhone, then you can use any text editor e.g. notepad++ to edit the converted file
It is one of the Erica Utilities
http://ericasadun.com/ftp/EricaUtilities/
Erica has also ported her utilities to the firmware 2.0 version as well.
e.g. plutil -c xml1 com.apple.SpringBoard.plist
plutil: [command_option] [other_options] file...
Command options are (-lint is the default):
-convert fmt rewrite property list files in format
fmt is one of: xml1 binary1
If you have mac and installed Xcode, it comes with an Application "Property List Editor". plutil is available on Mac OS X as well.
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