Question

How can i get the lists for the authenticated user & the lists that user follows

Answer 1

This should work:

    var service = new TwitterService();
    service.AuthenticateWith(<your consumerKey>, <your consumerSecret>, <your token>, <your tokensecret>);

    var listsUsersLists = service.ListListsFor(listOwnerScreenName);
    var listsUserIsIn = service.ListListMembershipsFor(listOwnerScreenName);
    var subscribedToLists = service.ListListSubscriptionsFor(subscriberName);

As long as the authenticated username is the same as the name of the lists you are trying to return, private lists will be included too.