Ubuntu Natty 11.04 Pidgin Tray Icons
Source (required if based on other people's work):
Tray icon theme for Pidgin that works with Ubuntu Natty 11.04 dark tray icons in Ambiance.
Credit to original authors:
To install, simply extract the contents of the tar.gz file to /usr/share/pixmaps/pidgin/
You want to overwrite the existing 'tray' folder. Back it up to be safe.
Press ALT + F2 and run 'gksu nautilus' to access the pixmaps directory as sudo.