Mac OS X users can download Vice 2.3 which is a package of several related emulators. When downloaded, open the x64sc emulator and from the File menu select Smart attach Disk/Tape (or hit Command+O). Select Posts’s PRG file and before long you will see Jed’s blinking cursor. Adjust the emulator’s speed as necessary.
Of course you can still download the original Applesoft BASIC code and run it on an Apple 2 emulator. For OS X we recommend Virtual ][ which emulates the Apple ][, ][+, and //e. And if you happen to have an actual vintage Apple laying around you can use the audio file included in the source code package to load Jed onto it via the cassette port—just like the guys at Panic Software! See their blog post about it: An Apple //e, an iPad, and Jed.
Jed’s Other Poem is a music video for the Grandaddy song of the same name. And (perhaps) the world’s first open-source music video. You can download the Jed source code package to run on your Virtual II emulator or even your own vintage Apple II series machine. To do the latter just play the audio from the “cassette tape” source code file into your vintage Apple’s cassette drive port. You’ll need an audio cable with male mini-jacks on either end. (Read up on Apple DOS and the “LOAD” command, you’ll be fine.)
After Panic posted their version of the Jed video other Apple-related sites—such as Daring Fireball, TUAW, and 9to5 Mac—linked to it. The flood of traffic brought down Panic’s site temporarily. (We think that’s pretty hardcore.)