Allow Skype to integrate to Sametime just like AOL and others do today. I know this is more of a legal / marketing issue than technical. But I think everyone who is looking for this should get on record in this forum to help provide some incentive for all those ...
Create a connector to enable one to call buddy via skype. User can update their skype info if/as needed and expose it via location info. Consider as an option below the phone icon (Sametime call, Skype call) when info is available.