BT has inked deals with HP and Taiwan's HTC for the supply of converged devices for its BT Business Fusion service.
The HP iPaq 514 Voice Messenger is a dual-mode UMA (unlicensed mobile access) Windows Mobile 6.0 handset, to be launched by BT in "mid 2007", according to an HP statement.
Being dual-mode, the handset uses wi-fi and cellular networks for when away from a user's office or a BT Openzone hotspot.
The device from HTC, a company for many years famous for not pushing its own brand, is also based on Windows Mobile 6.0.
Figures from the Wi-Fi Alliance today show nearly 100 handsets have been Wi-Fi Certified since 2004, 82 of which have been dual mode.
ABI Research forecasts that in 2011 there will be 325 million converged wi-fi/cellular phones.