American Sign Language Dictionaries:
http://www.aslpro.com/
http://www.lifeprint.com
http://aslbrowser.commtechlab.msu.edu/browser.htm
http://www.signingsavvy.com/
http://www.handspeak.com/
http://www.masterstech-home.com/asldict.html

About ASL:
Taken from http://www.nidcd.nih.gov/health/hearing/pages/asl.aspx : American Sign Language (ASL) is a complete, complex language that employs signs made by moving the hands combined with facial expressions and postures of the body. It is the primary language of many North Americans who are deaf and is one of several communication options used by people who are deaf or hard-of-hearing.

Taken from the NAD (great resource!!):
"American Sign Language (ASL) is a visual language. With signing, the brain processes linguistic information through the eyes. The shape, placement, and movement of the hands, as well as facial expressions and body movements, all play important parts in conveying information.

Sign language is not a universal language -- each country has its own sign language, and regions have dialects, much like the many languages spoken all over the world. Like any spoken language, ASL is a language with its own unique rules of grammar and syntax. Like all languages, ASL is a living language that grows and changes over time.

ASL is used predominantly in the United States and in many parts of Canada. ASL is accepted by many high schools, colleges, and universities in fulfillment of modern and “foreign” language academic degree requirements across the United States."

About Deaf Culture/Community:
http://www.signmedia.com/info/adc.htm
http://www.pbs.org/wnet/soundandfury/culture/deafhistory.html
http://www.deaflinx.com/DeafCommunity/culture.html

Terms:

American Sign Language: a complex full visuospatial language using hand movements, facial expressions and body movements to employ meaning to words and grammatical measures.
Deaf: cultural term in reference to Deaf culture using American Sign Language. Hearing loss typically occurs at a young age and the individual is proud to be a part of the Deaf community.
deaf: refers to the physical loss of hearing.