Exchange Server 2007 logs lots and lots of information in text files: message tracking logs, protocol logs, agent logs, routing table logs, etc.
If you want to extract information from this logs (and believe, there's plenty of useful information in these logs) you can use some more or less complex PowerShell cmdlets or you can buy some of the available commercial software for that purpose.
Fortunately, there are a couple of nice guys (to say the least) that are willing to share their findings and their work with the rest of the World. A fine example of such a case is Glen Scales, who maintains the Glen's Exchange Dev Blog. Here's a list of the GUIs he built that can be used to extract nice reports from the available Exchange logs: