Add follow line to your /etc/apt/sources.list 

deb http://www.deltalima.org/downloads/pidgin-2.4.3-1_i386_etch/ ./

Than run  apt-get update && apt-get install pidgin  an you have the new version of pidgin installed.

This packages where build from the Debian Sid-Sources - a single Package build from the original 
Pidgin-Sources is available in the directory /old/