iPhone Push to Talk

Palringo enables vocal instant messaging, picture messaging and text-based messaging over the iPhone’s data connection.
Palringo works by integrating with several existing, popular messaging services: AOL’s AIM, Google Talk, Yahoo! Messenger, Gadu Gadu, ICQ, Jabber and Windows Live Messenger. This also means people can use Palringo to contact their friends using iChat, Apple’s instant messaging (IM) client.
Palringo presents an iPhone user’s IM contacts in a single, combined, presence-aware list, whichever IM service their contacts are using. This eliminates any need to switch between different IM applications in order to send a message to different contacts. Sending a voice, picture or text-based message are single-click operations.