1. You need a device with PalmOS 5.0 or better, and an SD card or internal file system (Tungsten|T5, LifeDrive, Zodiac)
2. Install "ljp.prc" using "install tool" & "hotsync" or copy it in "/Palm/Launcher" on your SD card
3. Upon first launch, it will create all the needed directories & register the .zem extension so you can hotsync the .zem files directly (the .zem files are the 'emulation modules')
4. Copy "ljp-stuff.zem" and the modules you want (nes->ljp-nes.zem, gb->ljp-gb.zem, ...) in "/Palm/Programs/LJP" (NOT in the system directory, for example "/NES") or use the install tool & hotsync. If you use hotsync to do this, be sure to run LJP once before to register the .zem extension. (needed after each crash/reset too!) (into the SD Card)
5. Copy your roms in the right folder, depending on the system (see directories layout below) using either a card reader or the "mp3" trick (rename the ROM file to .mp3, .prc or .pdb, hotsync it to the SD card and use a program like FileZ (freeware) to rename to the original extension and to move the file to the right directory). There's also a (shareware) program called Card Export (from Softick) which turns your Palm-powered PDA into a card reader. LifeDrive/Tungsten|T5 users can also take advantage of Drive Mode to access the SD card/internal volume directly.