aMSN is a free open source MSN Messenger clone, with features such as: Webcam, Costum Emoticons, Skins, Tabbed Windows, Chat logs, and a lot of features that the MSN version for mac doesn't support.
10.3.9 PPC Available at this adress:
http://prdownloads.sourceforge.net/amsn/amsn-0-96-RC1-PPC.dmg?use_mirror=heanet
For 10.4 universal
http://prdownloads.sourceforge.net/amsn/amsn-0-96-RC1-Universal.dmg?use_mirror=heanet