There are lots of ways that you can be involved in your community and have a say. Here's a list of links you may be interested in:
Boards and committees
Kids on Government Boards and Committees in NSW
Reach Out's Youth Advisory Board (ROYAB)
Community
Get involved in Youth Week
100 ways you can make a difference: Simple things that you can do to make your community more liveable.
Community Builders' teens turning things around
Youth Action and Policy Association
Foundation for Young Australians
Entertainment
The Crew: behind the scenes with Aussie youth
Indent - Independent Entertainment Network for Young People in NSW
Schools
NSW Student Representative Councils
The Australian Curriculum Studies Association runs projects in which school students can participate