Update: Just received this correction from CounterPath's p.r. agency:
On April 22, 2007, it was reported that CounterPath Solutions, Inc. released a new mobile VoIP client in Europe called X-PDA. This information is false. CounterPath Solutions, Inc. has not recently launched a mobile VoIP client, nor does it sell or support a product named X-PDA. CounterPath Solutions, Inc. is not affiliated with Global IP Telecommunications.
Developed by VoIP softphone solutions developer and provider Counterpath, this client is optimized for HP iPAQ rx1950 series (Windows Mobile 5.0 for Pocket PC) and HP iPAQ hx2004 series (Windows Mobile 5.0 for Pocket PC), 400 MHz CPU or higher. Price is listed at 39,93 Euros for the 240x240 version (above). That'd be about $53.25 U.S. A 240x320 X-PDA is also available. That'd be 32,68 Euros, or about $44.35 U.S.
X-PDA sounds like it could have potential, but why not the loud marketing push as of yet? You'd think that this would be a substantial subscriber force-multiplier for Vonage, but nary a peep from them. My thinking is that Counterpath has been concentrating on the device integration and functionality rather than the VoIP provider alliances part. Maybe they feel they need to work with a wider selection of devices before they pursue the alliances? If I were Counterpath, I'd follow a parallel track for each. Near as I can tell, Counterpath may think it is too early to publicize services alliances. The problem with that strategy is until the noise is turned up, you are not going to hear of clients such as X-PDA.