dont use pidgin amsn is better, atleats when you installed it with antialias fonts, you can install it via yum like this,
first remove your old amsn then.
rpm -ivh http://download.tuxfamily.org/rpm/dr...1-2.noarch.rpm
yum install --enablerepo=drpixel-testing amsn
if you want to reduce font size You must go to : Account, Preferences, Appearence, Change Font.
Default font is Nimbus Sans L, 11, I choose Nimbus Sans L, 8.
You must restart amsn to start using the new font.