First you need to install simplejson:

easy_install simplejson

Now you can dump data to JSON:

import simplejson as json

class Something:

    def __init__(self):
        self.test = "test"

    def to_json(self):
        return json.dumps(self.__dict__)

Or if you have complex objects:

import simplejson as json
class Something:

    def __init__(self):
        self.test = [Other('a', 'b'), Other('a', 'c')]

    def to_json(self):
        return json.dumps([p.__dict__ for p in self.devices])