Yeah, they've been around for decades at least. Over here the B12 injections are usually a sign of an alcoholic as they're useful in overcoming hangover; although sometimes they're legitamitely prescribed for anemics. I don't believe the supplement pills have the same effect though.
Hehe, I didn't know about the other uses...
SWMBO had surgery which reduced her ability to absorb vitamin B, but I'm sure she'll be interested to know of the hangover cure!