The Switcheroo program is designed to run on any Palm OS device running Palm OS version 2.0 or later. In addition, Switcheroo requires HackMaster, EVPlugBase, TealMaster, or X-Master to be installed in order to run. All four of these applications are programs that manage system extension programs ("hacks"). HackMaster is shareware and may be downloaded from DaggerWare. EVPlugBase is free and may be downloaded from PalmGear H.Q. (just enter "EVPlugBase" into the Search field). TealMaster is shareware, available from TealPoint Software. X-Master is freeware, which you can find at LinkeSOFT's Web page.
Switcheroo is free software, distributed under GNU General Public License. If you'd like to take a look at the C source code (or use it for your own nefarious purposes), it's included with the program. The source may be built with the Palm PRC-Tools version 2.0 and the Palm OS 3.5 SDK.