displaying separate page with user profile

Do you want to also display all posts by an author? If not, you could create an author.php template for your theme (easiest way to do this is to copy the theme’s index.php), and where The Loop resides, replace it with code using the examples on the following Codex page to retrieve and display the author’s profile info:

http://codex.wordpress.org/Author_Templates#Custom_Author_Template

You can also display a combination of author profile and posts by retaining The Loop. Then to link to the author’s “profile,” make use of the_author_posts_link() template tag:

http://codex.wordpress.org/Template_Tags/the_author_posts_link