A cellular phone with an integrated PalmOS compatible handheld device.
Several derivatives of the Treo hardware exist, all made by Handspring, that operate on different cellular networks. The Treo 300 operates on Sprint's Sprint PCS network.
As a cellular phone, the device can be held to the face as a normal cellular phone, can be operated as a speakerphone, or can be attached to a headset. On average, reception and signal strength are good, and most conversations are clear, even inside monstrous buildings like the hotel/casino megaresorts on the Las Vegas strip. The device's phone list can accommodate thousands of phone numbers, as the cellular phone functionality is integrated into the PalmOS device as an application and thus has access to all the device's databases (including the contacts application).
As a PalmOS computing device, the Treo 300 is, for all intents and purposes, a regular PalmOS machine, with a Qwerty keyboard for data entry instead of a Graffiti area beneath the display (which is standard PalmOS resolution, 12-bit color). It has 16MB of memory, and has approximately 900KB of flash ROM available for application storage using tools like FlashPro1. The device is network-aware, and as such all applications installed on the device can directly access the Internet over the provider's wireless network. A web browser and a (amazingly, receive-only; you can install a separate utility to enable sending) SMS message viewer are included with the unit. Additionally, via unsupported third-party software, the device can be turned into a network access device for another computer, like a notebook or even a desktop system. By attaching the device to the computer's USB port, and running the enabler software on the Treo 300, the device appears to the hosting computer as a PPP-capable dialup device. When connected, though, throughput normally exceeds a normal 56k modem's performance by a factor of two.
Physically, the device is small and fits comfortably in a pocket. It is still not as small as, say, a Nokia 8260 series phone, and definitely feels larger when held to the ear during a call, but it is still a comfortable device to use and carry. It includes a rechargable (but, alas, non-removable) battery, but still weighs in at under 9 ounces.
Because the device runs PalmOS, it is compatible with Windows and MacOS, along with any open source operating system, such as Linux and FreeBSD, that supports the pilot-link tools and USB connections.
It's pricey, at $500 (before rebates and such), but is a very handy way to combine two commonly carried items into one slick unit.
I also personally happen to think it's pretty spiffy.
Footnotes
1 I tried with both
FlashPro and
JackFlash to pack known-ROM-safe applications into the flash area, without success. The unit didn't store the application properly in ROM, then crashed any time I tried to delete it from ROM (releasing the ROM space and uninstalling the application repaired the ROM, however).
Caveat Emptor.