Palringo is a very cool Instant Messaging program with push-to-talk VoIP functionality that runs on Windows Mobile phones, Symbian phones, and PCs. Palringo allows you to instantly exchange text, photos and vocal IMs with an individual contact or even a group.The multiple platform support enables you to stay in touch with your contacts whether you are working at your PC or on the go with your mobile phone. Further, Palringo also lets you send photos, vocal messages and exchange text IMs with other IM systems such as AIM, Yahoo!, Google Talk, MSN Messenger, and more. Thus, its excellent IM interoperability ensures you can at least IM other popular IM programs.
The coolest feature in my humble opinion is the push-to-talk (PTT) feature, which lets you instantly VoIP your buddies like a walkie-talkie or a Nextel phone. You can also PTT a group as well, which I can see being very addictive for teenagers -- but also a useful feature for mobile sales teams. It doesn't use SIP and it leverages the open source Speex codec. They're currently working on a Java version, which will add even more supported devices.
It doesn't offer outbound or inbound PSTN connectivity - it's strictly an IM and PTT application, but hey, who's complaining? It's free after all.
Go download your copy and check it out!p.s. Here's some Symbian screenshots
