Description of technique:
A great way to get a child who is already showing something verging on serious motivation to go out and sing and perform would be getting involved in a musical theater production at a local Community Theater, their school, a weekend music/acting training program, or a summer performing arts program. This will probably help them to become confident with movement on stage and with large crowds. Also, it never helps to start building a little performer's resume early on. They will be quite happy when they're 14 or 15 and seriously into music/musical theater. And because they have "experience", they end up having an advantage getting a part (even in a highschool musical). Also, it never hurts to build some seniority at a community theater, and they will be likely to meet kids who have similar interests to them, and witness some great older performers at work.

Appropriate age group(s):
6, 7, 8 and up, but depending on their role in the show, and maturity and patience!

Other suggestions or comments:
Also, it's a great idea to get a littler kid into a movement/dance class...it comes in handy when you know how to move!