AChecker is an open source web accessibility evaluation tool developed by the Adaptive Technology Resource Centre and other contributors. It’s available in a public, online version at http://www.atutor.ca/achecker/index.php. You can also download a local version in PHP and TinyMCE plugin.
The ACheck report generates a list of known problems, likely problems, and potential problems. Known problems are definite, machine identifiable accessibility barriers. AChecker identifies the line of code and offers instructions to fix it. Likely problems are those which require a human to check, such as nondescriptive links or layout tables. Potential problems also require knowledgeable human intervention. In both cases, the reviewer logs in and answers questions to verify whether the code is a barrier or not.
Once the site receives a clean report, you can paste a conformance seal in your Web Accessibility policy section.