MFS Communications and UUNET Technologies announced Tuesday that they plan to merge. The newly formed company will offer a full range of communications services including Internet access, voice, data and video transmission. The combined company will have current monthly annualized revenue of approximately $1.02 billion, with more than 50,000 business customers in North America, Europe and Asia served by 4,200 employees. MFS Communications will now have two groups, Telecommunications Services, led by Royce J. Holland, and Internet Services, led by John Sidgmore. Mr. Sidgmore will remain president-CEO of UUNET and upon closing of the merger, he will become a member of the MFS board of directors.