At this point, I don't think your will see an AgTalk app.  The problem with Apps is that they are OS dependent.  We would have to have an Iphone App, an Android App, a Blackberry App, and a Windows Mobile App at the very least.  Each OS requires different coding in different languages.  Features supported by one OS may not be supported by another.  We are looking into a dedicated mobile site that would be more friendly to mobile browsers, but it would still have to accessed via a browser.  But no target dates have been set for this.