Peter:

US coins w/ two heads can be one of two things: #1 An error by the US Mint, which are collectable & may be worth some serious money. Check w/ a local reputable coin dealer. #2 A "Magician's Coin". Magicians have been known to slice coins & solder two heads together. Look at the edge w/ a magnifying glass or jeweler's loupe and you may be able to see the seam. I have a magician's penny that is done so well that I can't see the seam w/ a 10X loupe. Most magician's coins are not worth more than a couple of dollars unless provenance to a famous magician is established. Just curious, what are the date(s)?

Hope this helps,

Dave Smith in NH
"Live Free or Die"