So there is an argument brewing online… this fella in Ohio Giovania at High Street Tattoo claims to have come up with the finger tattoo idea and wikipedia is giving partial credit by saying he brought it back to popularity in 2003 and through the internet it exploded in popularity.
From Wikipedia…
The finger mustache tattoo, otherwise known as the “fingerstache”, is a tattoo of a stylized mustache on the index finger. The finger is then placed between the nose and the lips, making it appear that the wearer has a mustache. Its particular origin is unknown, however, the recent revival dates to the summer of 2003 in Columbus, Ohio, where a local tattoo artist began tattooing mustaches as a joke.[1] Photos and stories about the tattoos spread to the internet, becoming a minor phenomenon after landing on the forums of popular comedy website Something Awful.
Also interesting news… there is a social network that is only about the finger tattoo: fingerstache.com