Change is an extremely difficult pill to swallow for many churches. Some churches change too quickly and alienate people, some change too slow and simply die off. Aubrey Malphurs in one his best books, A New Kind of Church, writes on the theology of change. Dr. Malphurs looks at the changing culture (pretty much every religion save Christianity is growing), and how different churches change (and should they?).
The meat of the book looks to develop a theology of change for churches. Dr. Malphurs looks to help the church get healthy. But this is not something that can or should be done without help. Churches need to develop the aforementioned theology of change as well as a theology of culture, and understand what a local church actually is.
Dr. Malphurs basically says that churches need to adapt (in methodology, not theology) in order to have any kind of impact. "A church's view of change will have a major impact on its ability to minister." Dr. Malphurs says that a good theology of change consists of function, form and freedom.
Functions are those mandates upon all churches which never change, are timeless and nonnegotiable. Among these would be the five purposes (whether you are a Purpose-Driven church or not). Forms are just the opposite - those things which are negotiable, which can change and are not mandated by Scripture. Among these would be types of evangelism (bus ministry, Sunday school, door-to-door witnessing, etc.), translation of Scripture used in preaching ministry, and such. Freedoms look at the implications and limitations of forms and change itself.
Having a theology of culture is also vital. For more on this concept, seek out the book Everyday Theology, edited by Dr. Kevin VanHoozer. It is an excellent work on the necessity of interpreting culture and how to read cultural trends.
Dr. Malphurs also stresses the importance of church consulting. This is something I can vouch for, a little. My dad, Jim Fann, works in Church Health for the EFCA and this is what he does - consult churches on models of ministry and developing theologies of change and such.
I have traveled with him on occasion and heard him speak to churches about many of the same principles Dr. Malphurs lays out in his book. Getting an outside consultant has proven quite useful to churches and being able to evaluate their situation and help churches move forward is what they do.
This book is also equipped with a couple audits and evaluations which will help you decipher what the readiness of your church is for change as well as a ministry values audit. This is a very helpful and practical book.