APA offers the following guidelines for citing a computer program/software/programming language (under the "Other electronic media" section):
Reference list entries are not necessary for standard off-the-shelf software and programming languages. Provide entries for specialized software or programs with limited distribution.
In text, give the name of the software, the version number and year.
Do not italicise the names of software, programs, or languages.
If an individual has proprietary rights to the software, name him or her as the author; otherwise, treat such references as unauthored works.
Immediately after the title and version, identify with a source type such as [Computer program], [Computer language], or [Computer software].
If no version number is available, include the retrieval date.
If the program can be downloaded or ordered from the web, give this information in the publisher position.
Schoonjans, F. (2008). MedCalc Statistical Software (Version 188.8.131.52) [Computer software]. Retrieved from 3D2F.COM Software Directory: http://3d2f.com/programs/13-638-medcalc-statistical-software-download.shtml
Accurate Personality Test [Computer software]. (2007). Retrieved June 19, 2008, from http://www.sharewareconnection.com/accurate-personality-test.htm
Tools and applications.
CultureGPS lite (Version 1.13) [Computer software]. (2011). Retrieved from http://itunes.apple.com/app/culturegps-lite/id297051765?mt=8
Pages (Version 1.5) [Computer software]. (2011). Retrieved from http://itunes.apple.com/us/pages/id361309726?mt=8&ls=1
Scott, C. (2011). Treasure hunt - the interactive boardgame (Version 1.1) [Computer software]. Retrieved from http://itunes.apple.com/us/app/treasure-hunt-the-interactive/id4425986640?mt=8
Consider looking at this page for a few helpful tips too (not APA though).