If you are scratching your head because the files in the %windir%\system32\LogFiles\W3SVC1 directory have no entries for the incoming MSMQ messages then you need to tick two boxes:

  • Open up Computer Management
  • Navigate to:
    • Services and Applications
      • Internet Information Services (IIS) Manager
        • Web Sites
          • Default Web Site
  • Right-click the web site and choose Properties
    • On the Web Site tab, tick "Enable Logging" and press OK
  • Right-click the MSMQ application underneath the web site and choose Properties
    • On the Virtual Directory tab, tick "Log visits" and press OK

 

From the Help:

Log visits
Select to configure IIS to record visits to this directory in a log file.
Visits are recorded only if logging is enabled for this Web site.

You should now start getting POST entries in the IIS logs:

2009-10-21 16:30:53 W3SVC1 10.0.0.1 POST /msmq/private$/webqueue - 80 - 10.0.0.5 - 200 0 0
2009-10-21 16:30:53 W3SVC1 10.0.0.1 POST /msmq/private$/webqueue - 80 - 10.0.0.5 - 200 0 64