The software, thankfully, is still extant; Infocom games were written in a kind of P-code (called, actually, z-code) and distributed with a P-code interpreter core, and not only open-source emulators for that interpreter but an actual compiler as well have been written to permit the P-code to be run on platforms the games never originally graced. In fact, new games written in this P-code are still being written. There is a home page at http://www.csd.uwo.ca/Infocom/ (mirror at http://www.vaxdungeon.com/Infocom/), and it is even possible to play these games in your browser if it is Java-capable.