To take a sign language class online, join Start ASL, a website that hosts numerous free courses that teach sign language. To supplement, use sites with videos, tutorials and dictionaries, such as Handspeak and Sign Language 101.
Start ASL has three ASL classes, as well as a fingerspelling class, divided into multiple units. Each unit page has a list of required and recommended materials, many that are free. Some resources are downloadable PDF documents that can be printed out for a physical reference, while others are specific tutorials and classes. The units have videos and exercises to help students become more comfortable with the language.
Handspeak has simple videos, a detailed glossary and tutorials. This site also has information about deaf culture and writing sign language, giving users a well-rounded education in the subject. There is also a brief overview of how to learn sign language that covers basic information, such as how long it usually takes to learn the language.
Sign Language 101 has multiple instructional videos that cover different types of signs, such as pronouns, gestures and body language, hobbies and clothes. Although there is a subscription available and the site accepts donations, the videos are available for free.