Ethidium bromide is the most common DNA stain available. There is a good comparison study: http://www.pulsenetinternational.org/assets/PulseNet/uploads/Underthemicroscope/pulsenettipsvol2.pdf if you prefer to avoid using it, as it is a powerful mutagen. Good luck!
Antonio, actually you can use silver staining for DNA separated on an acrylamide gel. Today I used Pierce Silver Stain kit for Mass Spectrometry, that I have on my shelf, it worked with the same protocol as for proteins.