Hardwarezone checks out the iPAQ hw6515 PDA from HP. Here's a snip:

Staying up to date with the latest information and being contactable wherever you are is all the rage these days and the latest product to peddle these conveniences is the HP iPAQ hw6515. Running within its 21mm thick housing is a Quad band GSM radio (850/900/1800/1900) that supports both GPRS and EDGE, thereby ensuring steady connection for telephony communications and information exchange regardless of geographic location..



Link: HardwareZone