innews:Xns9B3DBD0441A89jtjdfjdfjnbj@147.102.222.230:
Easy (done it myself): Draw schematic in whatever CAD program you want, export as graphics file. Load graphics file into MS-Word or whatever your favorite app is, format to your liking. Some text programs let you write over the imported graphics. If not you can do that with MS-Paint, that's what I use most of the time because it's easy.
It has those under Insert -> Symbol. In OpenOffice that would be Insert
-> Special Character.