I would like to ask about what are tha main features of functional programming?
If you are new to functional programming, read this http://haskell.org/haskellwiki/Introduction
What kind of software can i develop with this methodology?
I'm not sure what you mean by your question as it is very general. (If you are refering to the "methodology" in the FAD paper at http://www.cs.kent.ac.uk/pubs/2001/1152/ , I haven't read it so I can't help you there.) With Haskell, you can develop pretty much any kind of software, as any other programming language. See http://haskell.org/haskellwiki/Applications (If you want to develop a compiler or interpreter, you are in luck as functional programming languages are very good for developing this kind of software.) What kind of software are you intending to develop? Jared. -- http://www.updike.org/~jared/ reverse ")-:"