SmartReg for Pocket PC 3.5
the author of this app says:
Forgotten that registry change you made last week that you really wish you\\\'d never made? Not a problem if you made the change with SmartReg. Simply look in the change history list, view the change and then undo it! SmartReg is the professional Windows Mobile registry editor. It contains all the features you would expect of a standard registry editor PLUS complete historical change log, comprehensive undo/redo and regular expression searching.