Note: Not all fake books or real books have the same format, most will have sheet music with chords marked, some also have lyrics, a few have tablature, they are sometimes also available in different keys and arrangements to suit different instruments.
For an excellent collection of fakebooks to buy, checkout www.sheetmusicplus.com, who have a selection of some 1200+ to chose from, they also have good search facilities AND include content indexes for their books.
O Love, 'Tis A Calming Starry Night
O Love, How Deep, How Broad, How High
O Master, Let Me Walk With Thee
O Mio Babbino Caro
O Morning Star,How Fair & Bright composed by Philipp Nicolai
O Morro Nao Tem Vez (Favela) (Somewhere In The Hills)
O My Dearest Augustine
O My Soul, Bless Thou Jehovah
O No, John!
O Pato (The Duck)
O Perfect Love
O Promise Me composed by Reginald de Koven
O Rest In The Lord composed by Felix Mendelssohn
O Sacred Head, Now Wounded
O Sacred Head, Now Wounded composed by Hans Leo Hassler