That depends on the cat's disposition. Have you read anything on the web or in books about training your cat to be leashed trained.
You might want to try this link to start with:http://cats.about.com/
and look under behavior/training category or type in leash training on the search engine for that site or any search site.
There should be books also out there but I can't think of any at the moment.
Firstly though on a suggestion: Introduce your cat slowly to the leash - you don't want to rush this, otherwise you may never get your cat trained.
Never take your cat outsiede until he/she is comfortable with the leash for more than a few minutes.
(There is a new devise similar to a baby stroller that is designed for cats and small dogs so you can check that out as an option.)
I think the following link has the kitty stroller :http://drsfostersmith.com/
and look under cats then click on containments then click on Kittywalk Cat Containment.
Hope this helps a little. I'm sure others may have more suggestions and helpful hints.
P.S. Some would say it isn't safe to walk a cat in a park or allow the cat outside unless it's in a carrier so to play it safe I'd better cover myself. I don't personally let my cats outside due to many dogs living in the neighborhood, plus its busy(traffic) and many stray cats. Sphinx is leash trained and I am working on Kuce. I'm doing it in case we move a distance or some unforseeable situation arises.