We looking for a messenger solution for internal communication, is it possible we can restrict communication for MSN messenger to internal users only? If no, any good alternative?

How about Microsoft Office Communicator http://www.microsoft.com/uc/products/oc2007.mspx It's more than just a messenger for your internal group or corporate needs :)CEH.ECSA.MVP Windows Security

For this kind of topics, please discuss in Windows Live forum. How to use the Windows Live Solution Center http://www.windowslivehelp.com/solution.aspx?solutionid=572c601e-6820-4f8e-bc5e-32f576c47a23 Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.