Fink
From Aventine Solutions
Fink is a central repository and package manager for open source software ports to MacOSX with support for both PPC and i386. It is not the only animal of it's type but it seems to work extremely well and has most of what I need. warning! If you want to install packages which require an X Window manager, there are some special dependencies, complicated by the fact the Apple provides it's own (X.org and Xfree86 are the other open source ports). I had, for instance, a lot of trouble with GnuCash and found eventually that the X.org version worked best.
Fink is not yet ready for the faint of heart user (the average Macintosh user perhaps?) but is a must for technical users.
