Microsoft Corp is set to announce today that the Microsoft Network has become the first National internet service provider to offer Nortel Networks Inc’s Internet Call Waiting service. MSN internet access subscribers will be able to take call waiting and caller ID to the web, so they know who is calling and can manage incoming telephone calls while online, eliminating the need for a second telephone line. The service will be offered initially in three market areas: Seattle, Atlanta and San Diego, but Microsoft has plans to roll out the service in 50 major US metropolitan areas over the next few months.