1. Download and install darwinports directly from http://www.portcode.com/darwinports/DarwinPorts-1.5.0-10.4.dmg
2. Open Terminal and run the following commands. Enter your password when prompted. 
	sudo port -d selfupdate
	cd /opt/local/var/macports/sources/rsync.macports.org/release/ports/net/rtorrent
	sudo port install rtorrent
3. "sudo port install rtorrent" will take a long time, it took me 20 minutes. Find something else to do.