I wrote an article for Bible Odyssey answering this question.
Bible Odyssey is an online initiative of SBL intended to communicate the results of scholarship to a popular audience.
The article is a response to several user questions related to the issue of "oldest Bible." I tried to explain that the answer depends on what one means by "oldest" (materially? textually?) and by "Bible" (a bound book? Protestant? Catholic?).
On the bottom right of the page there is also a related links section where I provide links to a few of the manuscripts and editions mentioned in the article.