TinyCAD is a program to help you draw circuit diagrams. It comes complete with symbol libraries to get you started straight away. As well as being able to simply print your designs, you can use TinyCAD to publish your drawings by copying and pasting into a Word document, or saving as a PNG bitmap for the web.

You can use TinyCAD as a front end to a PCB layout program (see the links), by getting TinyCAD to create a netlist of your circuit.