If you are using a Mac PowerPC then try
MSN Messenger 2.1:
http://www.mirrors.ausmac.net/ftp/Communic...nger-21-ppc.bin
Or, for old MacSoftware:
http://www.ausmac.net/
Also, try searching Google for 'Mac 68k' (if you don't have a PowerPC).
(For those who don't know, 68k is the older type of processor that was used in Macs up until 1994 or 1995.)