Loudtalks Lite for Windows Mobile - turn your device into a walkie-talkie
Loudtalks Lite is a free application for Windows and Windows Mobile that allows you to communicate in push-to-talk mode, that is, as on a walkie-talkie. The project was released in the fall of 2007, but it became really interesting now that we released a version for mobile devices.
Support for all versions of Windows Mobile since Windows Mobile 2003
Interface with which you can work with your fingers, stylus or "iron" buttons
Talk traffic ~ 60 kilobytes per minute
The traffic in the mode of doing nothing with a contact list of 10 people ~ 3 kilobytes per minute (theoretically, it can be reduced approximately 5 times, but the hands have not reached yet)