For those of you who might want to 'brush up' on the thinking that accompanies how we might respond as a church after Christendom, Stuart Murray has a book called 'Church Afer Christendom' and one called 'Post-Christendom'. They are weighty books, although very good. There are also others in the 'After Christendom' series.
However, if you don't have time to wade through a book, I have discovered a Study Guide for 'After Christendom' which summarises the message of the book, gives some practical helps and then some good questions to ask. Maybe you have a book club or something, or a leadership team you could explore this stuff with. Might just help you reposition yourself for mission in post-Christendom west. Certainly Europe, Australia, New Zealand are further on into post-Christendom than, say, the United States and Canada but still, helpful stuff.
Its worth pointing out that even by the term 'post-Christendom' that there is a new era to come. It is dawn, twilight, where the old is fading and we enter a period of night....but hey, joy comes in the morning and we are at a stage of history where the creative church reincarnates itself to communicate the ageless gospel to a new world. Exciting times.
Anyway, here is the link to the study guide for those interested. http://www.anabaptistnetwork.com/pdf/afterchristendomguide.pdf