Does your Palm have a memory expansion card slot? What type of Palm is this? How much free memory does it have? (you can check that in the "Info" screen, accessible in the "App" menu in the application launcher)
Assuming it's running Palm OS OS 4.0 or later, it should be possible to install a stripped-down version of PlecoDict with handwriting recognition - I can tell you for certain once I know what type of Palm it is.