I know you can buy cheap USB "microscopes" that plug into a PC, but I made this one more for convenient workshop use and personally I hate having to tie up a PC by having a tool plugged into it.
Nice idea, I've been thinking of using a web cam for the same thing, but using yours w/o the computer would be a real "nicety". I'll have to keep my eyes open
at the recycle pile....
Nice writeup Roman - I use a similar setup with an old Panasonic camcorder (with macro function) and a composite to VGA converter.
I also have a spare composite input to my CCTV multiplexer/recorder which is also hooked up to the 17" Monitor so could use that when I find a suitable spare camera (which I have around 10 of floating around the workshop).
Something members might want to consider is one of the Logitech HD webcams - these can be purchased for £10-£20 if you keep your eyes open and will happily stream at 20fps at 1600 x 1200 (frame_mjpeg). The lenses are refocusable and can be removed and replaced with a better macro lens if needed. I use them for CCTV but have fancied building a half decent high magnification inspeciton device.
I've still been fiddling with the lighting and diffuser, it needs the right balance of enough light to get good camera contrast, and diffuse enough to get good visibility without white and dark spots, but if it is too diffuse the shadows wash out and the PCB starts to look flat and "2D" and the solder is harder to inspect, as solder joints need to be seen as a 3D shape.