ATLANTA (Bloomberg) — International Business Machines Corp., the world's second-largest software maker, will sell instant-messaging programs to small and medium-sized companies to woo them away from Microsoft Corp. products.

The Lotus Sametime Entry messaging software will cost $20 per user and will be released in the first week of December, IBM spokesman Mike Azzi said yesterday. The program lets users exchange short messages and see when colleagues are available.

IBM is trying to attract instant-messaging customers who are put off by the cost and unnecessary features included in rival products, Azzi said. Companies with fewer than 1,000 employees make up IBM's fastest growing business and represent a market the company values at $32 billion.