The University of South Florida at St. Petersburg has put together a great list of free assistive technology tools, which are organized by access needs. 

The following Assistive Technology tools are free to use and are organized by access needs.

Screen Readers

• Non-Visual Desktop Access (NVDA): Fully-functional screen reader for the Windows Operating System. It has the ability to run from a USB drive with no installation.
• Fire Vox: Talking browser extension for the Firefox web browser.  Basic features such as identifying headings, links, images, and navigational assistance are included.
• System Access To Go: Fully-functional screen reader for the Windows Operating System that runs from the web. It also works as a talking screen magnifier. It prompts for a download to maintain connection with the web client

Screen Magnifiers

• Virtual Magnifying Glass: Cross-platform screen magnifier. Magnification ranges from 1x to 32x.  Viewing window width and height can be adjusted.
• CLC Star: Browser extension for the Firefox web browser. Allows for enlarging images, increasing font size, changing font style and color, changing background color, enhancing focus indicator, increasing link and word spacing, and more.
• System Access to Go: Fully-functional screen reader for the Windows Operating System that runs from the web. It also works as a talking screen magnifier. It prompts for a download to maintain connection with the web client.

Text-to-Speech Output

• Natural Reader: Converts text to speech and can create audio files in mp3 or WAV (i.e. for iPod).
• PowerTalk: Speaks any presentation or slide show running in Microsoft PowerPoint for Windows.
• ClickSpeak: Browser extension for Firefox web browser. Mouse-driven interface that reads text based on point-and-click interaction.
• Word Talk: Plug-in for Microsoft Word that will speak the text of a document and highlight as it reads. It also includes a talking dictionary.

Text Presentation

• WordFlashReader: Flashes each word of a document sequentially on the screen. Font size, type, color, rate, and amount displayed can be adjusted..

Typing Tools

• LetMeType: Typing program that analyzes your typing and predicts words in order to increase typing rate. Works with most word processing and text input programs.
• Click-N-Type: On-screen keyboard that can be controlled with a mouse, trackball, touch-screen, or other pointing devices. Works with all word processing and text input programs.

Organizational Tools

• Downloadable Mind Mapping Tools:
  • XMind
  • FreeMind
• Web-based Mind Mapping Tools:
  • Bubbl.us
  • Mind42
  • MindMeister
• Web-based Bookmarking and Note-taking Tools:
  • Delicious
  • Diigo
  • Evernote