Armonk, N.Y.--Add IBM Corp. to the list of companies out to get a piece of Internet business-to-business start-ups. The company announced on Friday it has created a $500 million venture fund, earmarked for investment in firms that design ways to use the Internet to link supply-chain trading partners. The fund, to be managed by IBM's global financing unit, will invest both capital equipment and cash. IBM is the latest in a string of companies out to trade cash, equipment or services for equity slices of new Internet businesses. CMGI, Andover, Mass. and Electronic Data Systems, Plano, Texas, each unveiled billion-dollar investment plans late in 1999, while Intel Corp., Santa Clara, Calif., and Comdisco, Rosemont, Ill., have each assembled Internet business portfolios through cash and equipment investments.