I currently have an adult student who started taking lessons so she could one day play the piano for her church. I find that incredibly noble and inspiring. Since taking her on as a student, I have been looking out for materials that would help her become a functional musician for contemporary church services. I have been pleased to find that Alfred has a very nice series called Sacred Performer Collections. The following three books have especially caught my eyes:
Sunday Morning Praise Companion, arranged by Victor Labenske
If you are looking for one must-have book of Christian hits, this is it! It features 33 technically accessible arrangements that sound professional and sophisticated, yet require minimal preparation time. The melodies are beautifully arranged, with abundant use of sequences and a variety of accompaniment figures. Playing through this book gives the intermediate/late intermediate level pianists a crash course on the study of contemporary harmonic progressions, rhythmic patterns, and ways to bring out and accompany a simple melody. Each piece has a suggested performance time, making it easy to plan a program.