Learning PCB Design

I originally was going to use a protoboard to build the Bender Sequencer. That is the method I have always used to make "permanent" circuits. But, I decided to try designing a circuit board. I had already learned ExpressSCH for creating schematics, so I started playing with ExpressPCB. It is very easy to use and has a user interface that is almost identical to ExpressSCH, so the learning curve was very short. I have been searching online for information on good PCB design. I’m learning a lot and I redesign the board completely every few days.