I use Google's Picasa to manage my collection of photographs. Although Picasa is able to show images in RAW format, more often than not the quality is poor. Nikon's free ViewNX usually is much closer to the reality. But ViewNX lacks most of the management functionalities of Picasa. Which is understandable, because Nikon sells their own image management solution, Capture NX.
For a lot of tasks, I am happy with Picasa, but from time to time I would like to switch to ViewNX. So I created a new button for Picasa, that lets me open the current image or folder in ViewNX. Thanks to the Picasa Button API documentation and the Gimp Button as example, this was a matter of half an hour. Just click this link to install the button in your Picasa application.
Unfortunately, the button works only on Windows. The installation of ViewNX on Mac OS X seems to be non-standard (it is not installed as a package), so it is not possible to use the button there.
Update: Nikon released version 2 of ViewNX a few days ago, and of course the method for locating the executable has changed... Click this link to install an updated version of the Picasa plugin for ViewNX 2. And the plugin still does not work for Mac OS X, I'm afraid.