Content analysis is a research method that examines media or textual sources for the presence and/or frequency of words, phrases or concepts as indicators for societal and topical themes or significance. There are a multitude of tools and strategies, dependent on the material being studied: the following sources can provide some background and guidance:
The libraries also have some relevant manuals and handbooks to get started:
There are proprietary applications (for a fee) as well as open source tools (free) that provide various features for content analysis. Some of the more common statistical packages (such as SPSS, Stata and R) may have add-on modules that provide this kind of functionality: these would allow a researcher to leverage a system with which they are already familiar and increase its utility.
The resources listed herein emphasize open source which means they are freely available, but as such, they may be continually in development and the support for the product may be minimal:
Atlas ti (in OAL lab) - http://guides.library.illinois.edu/c.php?g=347981&p=2345710
NVivo (base app is free; additional functionality may require purchase) - http://libguides.rutgers.edu/danadata/Nvivo