Kicad - schematics, PCB and more
"Kicad is an open source (GPL) software for the creation of electronic schematic diagrams and printed circuit board artwork."
I have used Kicad to draw a lot of schematics and design the PCB for those schematics.
You may not find any component in its included libraries but it is easy to define your own.
The learning curve is not so step and you can find some good tutorials on Internet.
Here are some usage tips:
> I do not have the posibility to order double sided PCB at decent prices (and I mean with transport included) so I have to manually build my own or order only single sided PCB. Considering this fact, drawing the schematics such as the PCB will be easy to build manually or single sided is a must for me. The easy process of defining components allowed me to define the ICs as they are in the package so I have a pretty good ideea of the PCB right from the schematic drawing process.
> The PCB drawing component allows for precise printing of your drawing. If you design mechanical components in the free version of SketchUp you will have a problem printing them in real size - well, I have used Kicad's PCB creation tool to design 2D mechanical components for cr4.
> Schematic export for web. I export the image to SVG format: "File->Plot->Plot SVG", edit the file with a text editor to replace the colors as I like, load the SVG file in Gimp, scale and export it to png.