Like with any language, the best way is not to learn it from a book, or other source, but from native speakers. Get involved with the deaf community, take a course at a community college, or something else.
That said, there are some sites that can help you along the way:
Here is a great place that will get you started. It’s at: http://en.wikipedia.org
Look here:
http://en.wikipedia.org/wiki/American_Sign_Language_alphabet
This one is for basic signing… http://www.babysigns.com.
Like with any language, the best way is not to learn it from a book, or other source, but from native speakers. Get involved with the deaf community, take a course at a community college, or something else.
That said, there are some sites that can help you along the way:
http://www.aslpro.com
http://www.commtechlab.msu.edu/sites/aslweb/browser.htm
These sites are both slightly outdated, and are regional to Texas and Michigan, but do offer some basics.
Good luck, and hope you get involved with the deaf community and learn to love sign.