A simple Serial terminal in Processing.org allows for saving (part of) serial data to file
This simple terminal shows all incoming traffic in a large screen (no scroll) page is refreshed when full Data can be saved to file when the recording button has been pressed. User can send data over Serial to other application
Baud rate can be selected.
This will not win a beauty contest, but it fills a need when debugging (Arduino) applications. The saved data is stored in a .txt file format mmddhh-mmss.txt, each recording in it's own file