The ILY
handshape is probably the most
universally-recognized sign from
American Sign Language, and is a
shorthand way to say
I love you.
Formed from a combination of the letters I, L, and Y, the handshape is made by folding down the middle and ring fingers from the open flat hand. (The French Canadian version of ILY only folds down the ring finger.) This handshape is also used for the sign airplane and words related to planes.
The ILY sign is affectionately used by family members and friends, but it has also become the representative sign for anything with a sign language motif. The ILY can be found on keychains, letter openers, jewelry, and just about anything that could bear a logo.
Photographs: http://www.handspeak.com/i/ily.html