The Pidgin library, libpurple, has received a voice and video communication framework in this major update. Right now though, it's just that, a framework. The only Pidgin protocol plug-in that implements this support right now is XMPP, but greater protocol support is expected shortly.
For those interested in a customized environment, Pidgin 2.6 introduces support for themes. Themes just not alter the Pidgin user-interface, but can also set different sounds too with this new theming support. Both the audio/video support and theming capabilities come complements of last year's Google Summer of Code.
Beyond these major features there are nearly 100 points mentioned in the Pidgin 2.6.0 change-log, 221 bug tickets were closed, and many other new features introduced. The Pidgin 2.6 release announcement can be read on this blog. The Pidgin instant messaging program can be downloaded from Pidgin.im.