I have used X-10 hardware to control house lighting with ActiveHome Pro (and previously with ActiveHome on an older computer) which is the software provided by the maker. I have also used ActiveHome Vista. There is not much information about this application and unfortunately Hans Otten's notes seem to be no longer available (verified Aug 1, 2016).
The near demise of X10 and the intriguing possibility of using a Raspberry Pi as the hub of a home automation system have become the impetus to looking into using Linux based software. I have not yet made up my mind about what to use. In fact, like so many others, I am examining the possibility of writing my own control program. Note that Lazarus (and hence FreePascal of course) does run on this tiny computer.
In the meantime, I am using mochad on the Raspberry Pi. Control is done through web pages containing cgi scripts (written in python, PHP and Perl, the latter supplied with mochad). All this is very rudimentary as I know practically nothing about those languages. I am using lighttpd as the HTTP server because it has the reputation of being lighter than Apache.