Push-to-talk is coming to Android. Push-to-talk is the two-way-radio-type service of iDEN cellphones. In the US, this is mostly done by carriers such as Nextel and Boost Mobile. Unfortunately, the public service workers or contractors (and a bunch of regular consumers- my first cell phone was a Nextel) who would normally use this type of service are restricted to 2G networks, and other generally lagging technology.
A US mobile communications company, Harris Corp, claims that their BeOn tech will bring push-to-talk (PTT) into a new era. Their new iteration of PTT will include the old features of group calling, individual calling, distress calls, and dispatch services, but will also include a whole slew of new stuff. Some of these new features include user status, geo-location service, and texting.
The direct connect feature will be done through server-side tech. Basically, you are recording your voice, that data goes to a server, the server spits it out to your group or individual call. If it is GPS enabled, they also get your location. It's sort of like VoIP, but using PTT. This will be done over 3G or 4G networks.
BeOn was tested on a number of mobile operating systems, but Android was chosen by Harris as the platform of choice. Currently, Harris is in talks with a number of carriers regarding purchasing the platform. They hope to offer this service by next year.