AAIC is an autonomous atmospheric correction application that works with most commercial mulitspectral sensors. The process was developed by Applied Analysis Inc. (AAI) and is distributed as an add-on by BAE Systems for SOCET GXP and Intergraph for IMAGINE. Both companies versions will support LandSat 8 imagery with their 2015 releases. Although the application is not free, both companies offer no-cost evaluation copies if you are a current user of their software. Academic license are also available at a greatly reduced price. More information on AAIC is available at the distributors webpage and at AAI's webpage www.discoveraai.com, including detailed technical white paper with test results.
If you take the time to contact the AAIC distributors you may also want to ask for a demonstration license of GeoPalette, which is an autonomous land material identification/classification and bathymetry application.