I seem to recall that Chu Moy used JASC Paint Shop Pro for those schematics. He drew the individual parts by hand as a parts library, then assembled them for each new schematic.
I couldn't recommend the program myself. The last version I used was v6, before Corel bought it. I jumped ship to Photoshop because of the direction the program was going; it was no longer the simple, sharp tool I started with. My thought at the time was, if I'm being forced into powerful-and-complicated, I might as well go whole hog. A friend stayed on the PSP bandwagon for a few more releases before I convinced him to jump off, too, and nothing I saw in those releases made me regret the choice.
Maybe they've turned it around, and gone back to simplicity, but I doubt it. That's not the way software works. For about the same money, you can get Photoshop Elements, which if nothing else opens up a bigger world of training materials.
All that having been said, I don't see why you describe this method as "quick and simple". It's a specialist object achieved with a generalist tool. Given two equally experienced program drivers, the guy driving the schematic drawing program will finish first.
Personally, my vote for Best Dedicated Schematic Drawing Program goes to
gschem. It's got a bit of a learning curve to it — it works like nothing else you've ever used. But, having climbed it, I know of no other tool that gives schematics that are as clean and beautiful, or that come together faster. ExpressPCB's schematic editor is probably on par for speed, but the thick blobby lines it uses please me less than the sharp crisp lines of gschem drawings.
