Page Design: query_posts and search.php

Hello to all,
I hope to explain well ….

1) I built a custom teplate for displaying custom post.

To do this I used:

query_posts(array(
     'post_type'=>'portfolio'
));

In my case many posts have the same title, how can I make a sort of DISTINCT and display only one?

2) I found it very interesting the search page of my template that works like this:
http://www.nomedominio.it/?s=Parola+da+cercare
then all the posts that have the title ‘Search term’ will be shown one above the other with a look formatting.

How can I make sure that the results returned by query_posts (returned from step 1) remind me of this link?

Thank you.