Source: v 3.1:
for use with Pidgin 2.x. Here are the installation instructions.
Subversion: Instructions. The SVN build should work with the
current Pidgin Monotone build. If it doesn't, IM me: BillTompkins2 on AIM.
Fedora: You can find an RPM for Fedora Core at FreshRPMs or at Dries.
Mandriva: In the distribution, just "urpmi pidgin-encryption"
Gentoo: In the distribution, just "emerge pidgin-encryption"
Debian: In the distribution, just "apt-get install pidgin-encryption".
Ubuntu: In Ubuntu's "Universe" as Pidgin-Encryption.
Windows: Download the Win32 self-extracting binary.
Or, if you'd like, here are some instructions on how to build it yourself.