Yesterday Microsoft announced it was going to aquire Teleo,  a company that specialises in voice over IP software and services.

http://www.microsoft.com/presspass/press/2005/aug05/09-30MSNTeleoPR.mspx

At the minute is looks as if this aquisition will enable PC to Phone calls via MSN Messenger but I do wonder if it could be adapted and made to work for LCS too.  In the end it will depend on the pricing and the underlying technology but it is certainly something worth pondering for a while :-)