Follow the instructions on AngularDart's page on pub.
Study the AngularDart Tutorial to learn more about Angular in Dart.
Discuss AngularDart on the mailing list, ask questions on StackOverflow, follow +Angular on Google+, and follow @AngularDart and @AngularJS on Twitter.
Please file bugs and feature requests using the Github Issues Tracker.
Excellent read up on contributing.