http://theuniversaldownloads.com/IslBrowser09.zip
.. This is a little tool i've knocked together to let you peer inside .isl files. You can use it to load any .isl files that the server generates (including the auto-backup files, assuming you have that feature turned on), and view details of the archived-files (such as the PlayerRecords.dat) contained in the .isl. (e.g. you can view a list of players on your world, etc..).. If that sounds your kind of thing, give it a whirl and lemme know what you think..
Its probably quite useful for checking and recovering information on what players had when, and its also kinda interesting if you want to look at the general stats on how players are doing on your world. (You can sort the PlayerRecords.dat display by clicking the columns, making it easy to find specific players, or look at who's been most active recently etc..)
As usual, its all a bit under-cooked - more options and abilities to extract/parse/remove/edit files in the archive may well come in the future if im drunk enough ;]
