American Sign Language Alphabet
The American Sign Language Alphabet is a set of alphabetic finger signs for manually spelling out words, generally used for words that do not have available signs for expression within ASL, such as proper names, technical terms, foreign vocabulary, and so forth. Also very useful if you don't know signs. There is also included a set of numbers for the expression of digits. It is based on an old Spanish manual alphabet that goes back to around the 17th century or before.
The Letters for signing in American Sign Language:
And here are the sign for the numbers 1-10 in ASL
You can also browse a nice collection of ASL resources, dvd's and books.
ASL University has a helpful page of exercises and quizzes plus other information on ASL Finger Spelling. There is also a Advanced Practice Tool here that allows you to practice receiving messages in finger spelling, with options for setting speed and size of words.
This representation of the American Sign Language alphabet was made using David Rakowski's Gallaudet fingerspelling font, which can be found here.