In addition to the built in Event Viewer app there are quite a few script\parsing utilities out there to help with more advanced\structured processing of Eventlog\evt files.
One problem you may have is that older format event logs (.evt from W2K3\XP era systems) don't always play nicely on newer systems which use the binary .evtx format - the WEVTUTIL command can be used to convert the former to the latter.
In addition to the built in Event Viewer app there are quite a few script\parsing utilities out there to help with more advanced\structured processing of Eventlog\evt files.
Perl's win32::EventLog
Microsoft's Log Parser
One problem you may have is that older format event logs (.evt from W2K3\XP era systems) don't always play nicely on newer systems which use the binary .evtx format - the WEVTUTIL command can be used to convert the former to the latter.
Um, Event Viewer?