Michael already posted this tool but it is worth mentioning more than once.
If you don't know already what Log Parser Studio is then you definately have to check out this tool. It makes reporting for Exchange real easy!
Log Parser Studio is a utility that allows you to search through and create reports from your IIS, Event, EXADB and others types of logs. It builds on top of Log Parser 2.2 and has a full user interface for easy creation and management of related SQL queries.
Read the original Exchange Team post here:
Download Log Parser Studio: