If you want something really easy and intuitive to use, I would recommend the free software from ExpressPCB. It’s actually two programs, Express PCB for doing circuit board layout, and Express SCH for schematic diagrams. It’s sort of the MS Paint of circuit design. For example, I used Express SCH to make these schematics: 1 | 2. It uses a proprietary file format for ordering circuit boards from the company, but I’ve never actually ordered anything from them (although I have printed out circuit board designs from Express PCB and tried to use them as transfers for etching).
-Adam