Assistive technology (AT) is a generic term that includes assistive, adaptive, and rehabilitative devices for people with disabilities.
"JAWS Screen Reader - Hear an Example"
Screen readers are software that will take text on a computer screen and convert it to spoken word. They can also help a user navigate the visuals on their operating system and websites.
http://www.youtube.com/watch?v=IK97XMibEws&feature=related
"Low Vision? Enhanced Vision products have helped Kyle Bergum"
Magnifiers can be anything from the traditional pieces of specially shaped glass, to devices that hook up to a TV to magnify images.
http://www.youtube.com/watch?v=jSjaxbRYRV0
Braille is a system of representing the written word through a set of tiny bumps on a page. Grade 1 Braille represents each letter or number with a specific set of dots. Grade 2 Braille includes the 26 letters, but also includes contractions of words and punctuation. Grade 2 Braille is the most common type in use.
http://www.omniglot.com/writing/braille.htm
Guide dogs are one option for a blind person to navigate around obstacles, especially when in new territory. A guide dog is extensively trained and can provide many services to the person including leading them around obstacles on the street and helping to cross the street safely.
A service known as Read This to Me provides assistance to people with visual disabilities. The person faxes a document to the organization, and a worker from Read This to Me will call the person on the phone and read the document aloud.
http://www.readthistome.org/
Able Data, an online resource, provides information about numerous assistive technology devices.
http://www.abledata.com/abledata.cfm?pageid=19327&top=13134&deep=2&trail=22&ksectionid=19327