This is a traditional song and fingergame for toddlers and preschoolers. If you're trying to teach children about parts of the body, this is a great song to use. It's also a good "calming down" song. It's very gentle and uncomplicated, and encourages the child to focus on his or her hands, so if you're trying to transition from running activity to napping or lunch this song is pure magic.
Start by sitting with the child/children, face to face or in a circle, with both hands behind the back. Sing, to the tune of Frere Jacques (AKA "Go to Sleep"):
Where is Thumbkin?
Where is Thumbkin?
(Look around as if searching...)
Here I am
(Bring out one hand, with the fingers closed and thumb up)
Here I am
(Bring out other hand, thumb up)
How are you today, Sir?
Very fine, I thank you
(Waggle thumbs as if they are conversing)
Run and play
Run and play
(Put one hand behind your back, then the other)
SECOND VERSE:
Where is Pointer?
Where is Pointer?
(Repeat lyrics and activities from first verse, with only the index finger extended)
Other verses continue with the remaining fingers:
Where is Tallman?
(Try to control your urge to giggle)
Where is Ringman?
Where is Pinky?
Where is the family?
(Raise and waggle all the fingers.)
For such a simple song, a surprising number of variations exist. Some versions of the last line for each verse include "Go away", "Run away", and "Happy day". Numerous variations on the fingers' names also exist, including "feeble man" for the ring finger and "baby" for the pinky. There's no right way to sing this, but I personally prefer names that sound like actual people's names - Ringman sounds far cooler than "feeble man", and I think the anthropomorphic names stick best in children's minds.
This song is clearly related to the slightly more complicated finger dancing nursery rhyme "Dance, Thumbkin, Dance", but I can't tell for sure what the relationship is. DTD is included in many versions of Mother Goose, but this is not necessarily a reliable indication of its age. However, judging by the more old-fashioned language in DTD, and the fact that "Where is Thumbkin?" borrows the music from Frere Jacques, I would guess that this is, in fact, a relatively modern reinvention of Dance, Thumbkin, Dance. | 
