In windows just open up a command prompt (Start | All Programs | Accessories | Command Prompt). Using dos commands (especially "cd") navigate to the directory of interest. Type "dir" to see the contents. Type "dir > files.txt" to write the list into the file "files.txt".
I hope that helps. With a Mac you can do a similar thing with Unix, using the terminal window. Instead of ">", you use a pipe "|", if memory serves.
I hope that helps!