After a long period, I just built packages of microblog-purple and Mitter for Ubuntu in Personal Package Archive. PPA is a kind of personal repository for apt-get hosted at launchpad.net. As a result, you just need to add below lines to /etc/apt/sources.list.

deb http://ppa.launchpad.net/sugree/ubuntu hardy main
deb-src http://ppa.launchpad.net/sugree/ubuntu hardy main

And simply run apt-get to install.

sudo apt-get install mitter

or

sudo apt-get install pidgin-microblog