Keyboards are not only necessary for laptops and notebooks, but in my opinion, they are completely and utterly indispensable for any and all mobile communication devices (that is until speech recognition is perfected or computers can be controlled through thoughts). Unless one grows up learning to type on mobile phone number pads (and ironcally many kids of this SMS generation do grow up so...) you will aprreciate having a full size keyboard to do your typing. Most keyboards for smart phones and PDAs are either available with Bluetooth connectivity or with Infra-Red (IR) connectivity. This ensures that these keyboards can be used without the hassle of installing drivers and plugging in wires. Bluetooth keyboards are the easier to use and are compatible with almost all Bluetooth enabled devices. They are also easier to use because one doesn't have to align the keyboard with the smart phone or PDA just so to ensure that it works. Other than that, features for portable keyboards are fairly standard and at most what varies is the colour, size, weight, number of keys, ease of use, compatibility and comfort. So one still has enough to choose from (most keyboards for PDAs and smart phones require an OS - such as Symbian, Palm OS, Pocket PC, Windows Mobile, etc).
Accessories for the following brands are available at PDA Accessories: Apple / Ipod, Audiovox, Casio, Dell, Handspring, i-mate, MDA, Kyocera, Microsoft, Motorola, Nintendo, O2, Orange SPV, Palm, Qtek, Blackberry, Samsung, Sharp, Siemens, Sony, T-Mobile and Toshiba.
