GPS Receiver . There are Global Positioning System add-ons available for both the Palm and the Visor. You download maps to your handheld and the GPS modules show you where you are and how to get to area destinations. Be warned, though, the maps eat up a lot of memory. All other units, and the Handspring Visors and Pocket PCs, require an external modem or expansion card.
Internet access is extra.
Digital cameras . Palm and Handspring products generally work with a plug-in digital camera. With Pocket PC, only the Casio models will work with a camera. Don't expect super quality. Digital recorder .