There is this really cool site, which is free which allows you to make your own stories, but the type which allow the user to make a choice. Theres loads of stories on there and even I have made a few stories . I have given you a link to one of my stories, so you can see what i'm on about but there are loads of stories which are better than mine.
Here you go:
http://www.myadventuregame.com/story/The_Machine.aspx
Check it out!
My blog:
http://aint101blog1.wordpress.com/2012/02/13/novel-interface-5/
Funny quotes:
"We are all atheists about most of the gods that societies have ever believed in. Some of us just go one god further."
Richard Dawkins