An Android VoIP App
I always beleieved that sooner of later VoIP will catch up with smart phones. I made some small little apps for this purpose. And now we see VoIP over Android getting common on Android and other phones.
I have worked with two companies as their Android/SIP/VoIP developer, and in fact still working as a consultant for a big phone manufacturer for their UC360 series conference phone, which provides SIP based conferencing solution using Android platform. Its the best conferencing solution I have ever seen.