Script has been updated, se below for information and link to script.
Changes as of 2008-05-18:
Now it is possible to decide how many local copies of backup files to keep based on file timestamps. Lets say that we do backup once a night at 12 and want to keep to 2 successive copies locally and delete the rest, the by setting ZimDeleteTimeSet to 3000, which is 2880min which is equal to 2 days + 120min as a margin in case the backup should take a little longer than usual, we will keep the number of files we want locally. The time is set in minutes to ensure some degree of flexibility.
Also added some help in the script for user configurable settings.
Download here:
Script Download