The Virginia Board of Elections web site has a feature that documents all changes to the reported election returns, as they have evolved over time. You can get to the accounting by going to the election results for the office you’re interested in, and then clicking the “See History of Changes” link. This link takes you there directly. Totally cool!
It’s hard to resist downloading the reports into a statistical package and then doing some data analysis on it. For instance, here are the net changes to each presidential candidate since the returns were originally posted: