Here's the latest version of Reatune (put in your plugins/fx folder):
http://reaper.fm/files/reatune.dll
It has the following changelog:
+ ReaTune: added reference frequency adjustment
+ ReaTune: bigger tuner display and more colors for the cents display
+ ReaTune: slightly more accurate pitch detection
+ ReaTune: better graph display
+ ReaTune: configuration remembering
Automatic pitch correction and harmonizer modes coming soon!
-Christophe