The book : "The New Testament Documents: Are They Reliable?" has been a great help to me in my search for the origin and reliability of the book we call "The Bible".
A few extracts:
"The Christian gospel is not primarily a code of ethics, or a metaphysical system; it is first and foremost good news"
"The New Testament was substantially complete about AD100, the majority of the writings being in existence 20-40 years before this" [p12]
"If the New Testament were a collection of secular writings, their authenticity would generally be regarded as beyond all doubt"
"It is a curious fact that historians have often been much readier to trust the New Testament records than many theologians. Historians like WM Ramsay, Ed Meyer, and AT Olmstead have protested vigorously at the excessive scepticism of the theologians in dealing with the historical writings of the New Testament" [p15]
"There is much more evidence for the New Testament than other ancient writings of comparable date" [p15]
"There is in existence about 5000 Greek manuscripts of the New Testament in whole or in part"
From an interesting article from google groups [well worth a read] I found a lot of interesting information.
The following is a list of non-biblical sources:
Lucian of Samosata
Flavius Josephus [another]
Plinus Secundus, Pliny the Younger
Phlegon, A first century historian
Letter of Mara Bar-Serapion
Lots more information is available at http://www.earlychristianwritings.com/