Redmond, Wash.--Microsoft Corp., IBM Corp. and Pfizer Inc. are forming a joint venture that will develop and market software to physicians. The companies will also provide consulting services. The software will be designed to help doctors save time by automating clerical and clinical paperwork tasks. IBM will provide much of the software and hardware, and Microsoft will provide its Internet platforms. Pfizer will be responsible for the marketing through its 8,000 sales representatives.