Installing a linux application in OS X - source or via package mechanism?
To answer some of your questions (there are a lot!) 
Not all programs written for Linux will install on OSX nor will they necessarily even compile from source. 
What"genre" of programs are you looking for? Things with a GUI, or command line programs or scientific?
In general I would recommend usingbrew first, and seeing if you can find the program you want there. Fink and MacPorts, etc, have become far more problematic.