there is a perl script that converts extended iis logs to ncsa.

its handy if youre migrating from iis to apache and want to keep your logs for stats etc

the perl script might not be perfect, but this java is, kinda

actually – all this is out of date now
you should be using google analytics for basic web stats
and awstats for anything else
im im sure awstats copes with the iis logs by now.
like
surely