Web/email server

I wanted to know if there was a low resource program available that would allow me to use my computer as a web/ ftp server? I want to post a no nonsense password protected site that is not published via a search engine but would still allow me and afew trusted friends to access and download information and programs that we can gather and store.One of my main concerns is low resource requirements as i do still want to be able to use my computewr in the normal fashion.