Sidecar for Android and iOS is launching today in what could be a very important addition to your phone call repertoire. Its most basic definition is a VoIP app, which provides free calls to American and Canadian numbers over WiFi or 3G. You register your number with the service and outgoing calls appear to be from your main number, like a regular cell call. In addition, to anyone who has the app installed, you can share photos, live video, contacts and locations without interrupting the call the data transfer works over existing data lines while the call is going on and seamlessly transitions to speakerphone when you move the phone away from your ear. The interface imitates a rotary phone in what could be seen as more than just an aesthetic tribute to the way it used to be; Sidecar attempts to make it easy to multitask while on the phone, something most people do already without realizing it. I tried out the app on Android and while the company was experiencing launch-day server issues, call quality seemed pretty good over 3G. Live video, which is called See What I See, is an excellent way to conference, and has the potential to be pretty popular for business users looking to collaborate on projects. The Whisper function also allows for text messages through the app itself. Most of the companys marketing materials emphasize that the app was designed for Android from scratch, and really takes advantage of the total integration paradigm that is more possible on Googles OS than Apples. You can set Sidecar to be your default calling app so when you touch the Phone icon on the homescreen it skips the default dialer.