Check out Global Integrity, “an independent, non-profit organization tracking governance and corruption trends around the world. Global Integrity uses local teams of researchers and journalists to monitor openness and accountability” (HT: Librarians’ Internet Index: New This Week).
There are limitations, of course, such that countries such as Venezuela or China are not listed as of yet. But Global Integrity might be one valuable tool to add to your “global citizen’s” toolkit.
And while we’re on the topic, don’t forget to add this to your toolkit as well: A Theory of Corruption, by Osvaldo Schenone and Samuel Gregg.