Post previews outside the loop

Hi Guys,

I know PHP, and I would like to display post previews (a link on the tiel and a short excerpt) outside the loop, i.e my blog is in a directory (mysite.com/blog) and I want to display post previews outside the directory i.e. on the homepage etc.

I suppose I can use the WP functions if I include the correct files, which files must I include that will allow me to do this.