One of the most useful tools I have ever used just released an update. Microsoft Log Parser 2.2 is now out.
Get it here – Microsoft.com
I have used this tool for many projects. To analyze server data for multiple sites and also for just straight traffic reports. There are many scripts you can write with this product. If you are not heard of the log parser, it allows you to run sql like statements against almost any log file, event log, Linux syslogs, and such. You can then store it as variables, xml files, CSV, or add to a .Net project.
I will post some of the common scripts I use. One such script I use frequently for our shared hosted sites is a Log Parser program that reads the URLScan log and reports stats. Our clients love to see that report – How many code read / cmd.exe attempts are being sent to their site.