The service, based on text messages, allows users to send and receive Hotmail email and chat with MSN Messenger contacts on their mobiles. There is no subscription fee but users do have to pay the cost of sending a text message, which is around 10p. The revenue from the service will be shared by Microsoft and Vodafone.
The service is planned to go live in May and will benefit the 7.4 million UK-based Hotmail users.
The announcement is part of a broad Microsoft campaign to link up with mobile operators. Across Europe, the Middle East and Africa 22 operators already offer MSN mobile services.