Sometimes it is handy to know where the various WHS specific log files are located.  For example, you may be tasked to provide various log outputs for trouble shooting or diagnostics purposes.

Windows Home Server Logs: 
%SystemDrive%\Documents and Settings\All Users\Application Data\Microsoft\Windows Home Server\logs

Windows Home Server Connector Logs (Windows XP):
%SystemDrive%\Documents and Settings\All Users\Application Data\Microsoft\Windows Home Server\logs
 
Windows Home Server Connector (Vista & Windows 7):
%SystemDrive%\ProgramData\Microsoft\Windows Home Server\logs

Windows Events Log Viewer
Remote Desktop into your Windows Home Server, proceed to Administrative Tools under the Control Panel section and open the "Event Viewer"

Alternatively or in addition the Microsoft Windows Home Server Toolkit 1.1 is extremely handy and makes it easy to look at your WHS Windows event logs.