You can generally find out about your local member or representative from the "Members" section of your parliamentary, assembly or congressional website. It is also usually possible to obtain your representative's email address or to link to the representative's websites and send an email direct to your representative.
Here are some of the more sought after sites. We will add more as we are able.
AUSTRALIAN PARLIAMENTS
NSW | VIC | WA | QLD | SA | TAS | NT
INTERNATIONAL PARLIAMENTS
United States of America - House of Representatives