Apple Computer and Digital Equipment Corp. announced a joint-development pact that they hope will challenge industry leader IBM. The project will eventually make it possible for programs running on Digital's VAX minicomputers to appear on the screens of Apple's Macintosh personal computers as though they were Macintosh programs . . . New World Entertainment Ltd. said it sold 500,000 shares of its series B preferred stock to Technicolor Inc. for $12 million . . . Iran's non-oil exports were worth $840 million in the last three quarters of 1987, an increase of 25% over the same period in 1986, Iran's national news agency reported. The most valuable exports were carpets, hides and pistachio and other nuts.