If you are interested in starting a dog park the best place to start is
by calling the city parks office and inquire whether there is already
interest expressed in a dog park, express your own, and feel out the
city's attitude towards starting a dog park.
If there is not a group already
established to lobby for a local dog park, start one! Approach local
dog owners about starting a dog park and give them a contact point
rather than just an "I'll call ya and we'll talk about it". Start a
Yahoo group or Google Group (so when you send one message it goes out
to everyone) and you can build membership and make plans to start a dog
park that way. You can just print up business cards to give to dog
owners you meet on walks and at events.
If you can help that yahoo group
grow for a few weeks and months you'll eventually get people with city
council ties and people who can really get stuff done. Additionally, as
the group snowballs and you are ready to start a dog park you'll have
plenty of people to sign a petition or to run a fundraiser when the
time comes.