Loriis7
This is a simple log file management app for IIS, in the isntall folder is a file called loriis7.config.xml this has 2 entries,
DaysBeforeZip and DaysBeforeDeletion. When the app runs it discovers all IIS log folders and starts to process each log file,
if the file is older than DaysBeforeZip it gets zipped up, if it is older than DaysBeforeDeletion it gets deleted.
Simply run the installer on your web server, modify the loriis7.config.xml file and schedule the app to run daily!