Once a site has been established, it is a good idea to make sure that the entire site is up to the standards. Many software packages, such as Dreamweaver, have built-in tools that test and render a report of suggested changes. If you do not have a software package, many online sources are available to test a site and its compliance.
Link to www.section508.gov evaluation tools: http://section508.gov/index.cfm?fuseAction=webaccess
Links to online options to test a web page: