For those of you who are not familiar with it, the Live Meeting service portal is a component LM customers can deploy to allow SSO against the an on-premise Active Directory.  This is an incredibly helpful tool for simplifying administration of the service and improve end user usability.  The portal also exposes web service to support these SSO scenarios in XML-API programs.

If you are interested in learning more you should check out this TechNet webcast describing how the Microsoft IT department deployed the service portal to maximize their users LM experience.  You can register here… http://msevents.microsoft.com/CUI/EventDetail.aspx?EventID=1032380133&Culture=en-US