The little gerber viewer that could!
Of course I’m talking about gerbv! For those of you who don’t know, gerbv is a free Gerber or RS-274X viewer that comes from the gEDA Project. It’s free, it’s open source, it’s cross platform… (quick link to windows version download here) and that’s awesome.
So, why do you care? Well, if you are building your own circuits and want to get a PCB made then usually the format you’ll need to export your design into is a gerber. The reason you should grab gerbv is to double check for errors. When you design a PCB in your favorite circuit layout tool, whether it be Eagle, Altium, or my favorite DipTrace, you should double check for errors.