GPS

With GPS-driven car navigation systems gaining in popularity, a couple of vendors (Garmin International, HP, and Pharos) have created PDAs with integrated GPS receivers and bundled navigation software, which provide voice-based turn-by-turn directions and maps. Typically you can't yet get both integrated GPS and integrated Wi-Fi in the same unit, but a small and growing number of devices are bundling both technologies--and sometimes Bluetooth and cell phone radios as well. If you want to add Wi-Fi or GPS, you should be able to do so via third-party products that connect either via Bluetooth (in the case of GPS) or through the handheld's expansion (SD) card slot.